(CNN) Donald Trump wants the American people to know that he realizes some of the things he's said have hurt people. Which people and what things, exactly, is less clear.

Speaking in Charlotte on Thursday night, he expressed "regret" over comments that "may have caused personal pain."

"Sometimes, in the heat of debate and speaking on a multitude of issues, you don't choose the right words or you say the wrong thing," he said. "I have done that."

Trump has spent more than a year scything his way through the campaign jungle, cutting down everything in his path -- along with a number of innocent bystanders -- en route to the Republican nomination. If he were to trace back his steps on an apology tour, it might take a while.

Here are a few of the places he could start:

The Khan family

After the parents of Capt. Humayun Khan, a US solider killed by a suicide bomber in Iraq, questioned Trump's sacrifices during a speech at the Democratic convention, the nominee fired back in a pair of interviews and on Twitter.

"(Khizr Khan's) wife, if you look at his wife, she was standing there. She had nothing to say. She probably -- maybe she wasn't allowed to have anything to say," Trump told ABC News , suggesting Ghazala Khan had been silenced by her religion. ( She wrote in an op-ed the next day that her pain is such that she has trouble speaking about her son.)

Trump targeted Khan's father the next morning on Twitter. Why? For talking to the press too much.

"Mr. Khan, who does not know me, viciously attacked me from the stage of the DNC and is now all over T.V. doing the same - Nice!" he tweeted Monday, August 1, adding more than 15 minutes later: "This story is not about Mr. Khan, who is all over the place doing interviews, but rather RADICAL ISLAMIC TERRORISM and the U.S. Get smart!"

Asked on ABC News Friday morning if the newly contrite Trump would offer the Khans a personal apology, new campaign manager Kellyanne Conway said, "He may."

Conway also said she hoped that "everybody who has criticized (Trump) at some point, for being insensitive or for mocking someone, at least shows some recognition and some forgiveness."

Judge Gonzalo Curiel

In late spring, Trump picked up his attacks on the judge overseeing a lawsuit against Trump University. He called Curiel, who is of Mexican descent, a "hater" and suggested, without explanation, "they ought to look into Judge Curiel."

"Everybody says it, but I have a judge who is a hater of Donald Trump, a hater. He's a hater," Trump said at a May 27 rally in San Diego. "His name is Gonzalo Curiel and he is not doing the right thing."

Speaking to CNN's Jake Tapper a few days later, Trump made plain his position : "We are building a wall. He's a Mexican. We're building a wall between here and Mexico." (As Tapper noted then, Curiel was born in Indiana.)

New York Times reporter Serge Kovaleski

In November, Trump mocked Kovaleski during a rally after the reporter disputed the candidate's claim that "thousands" of Muslims cheered as the World Trade Center "came tumbling down."

"Now the poor guy, you ought to see this guy," Trump said, as he twisted and contorted his body. "'Ah, I don't know what I said! I don't remember!'"

JUST WATCHED Trump mocks reporter with disability Replay More Videos ... MUST WATCH Trump mocks reporter with disability 00:45

Trump later asked for an apology from the Times and said of Kovaleski, "The problem is, he's using what he's got to such a horrible degree, I think it's disgraceful."

Muslims

Trump was angry with Kovaleski because the reporter, who had covered the New York City region during 9/11, refuted Trump's claim that local Muslims celebrated the attack.

"I watched in Jersey City, N.J., where thousands and thousands of people were cheering as that building was coming down," Trump said at a November rally in Alabama. "Thousands of people were cheering."

He doubled down a day later, telling ABC News, "There were people over in New Jersey that were watching it, a heavy Arab population, that were cheering as the buildings came down. Not good."

This was, as multiple news outlets repeatedly pointed out, false. Politifact gave it a "Pants on fire" rating.

Mexicans and Mexican immigrants to the US

Day one, speech one. Trump kicked off his campaign with a promise to build a wall on the US-Mexico border.

Here's how Trump explained the need:

"When Mexico sends its people, they're not sending their best," he said. "They're not sending you. They're not sending you. They're sending people that have lots of problems, and they're bringing those problems with them. They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people."

Megyn Kelly

After the Fox News anchor pressed him with some tough questions during the first GOP debate last August, Trump told CNN's Don Lemon days later that Kelly had been "ridiculous" and "off-base."

"You could see there was blood coming out of her eyes," he said. "Blood coming out of her wherever."

JUST WATCHED Donald Trump's 'blood' comment about Megyn Kelly backfires Replay More Videos ... MUST WATCH Donald Trump's 'blood' comment about Megyn Kelly backfires 00:52

Ted Cruz and his father, Rafael

On what would be the last day of Cruz's primary campaign, as Indiana primary voters went to the polls, Trump channeled a conspiracy theory promoted by the National Enquirer that said Rafael Cruz was in league with JFK assassin Lee Harvey Oswald.

"And his father, you know, was with Lee Harvey Oswald prior to Oswald's, you know, being shot. I mean the whole thing is ridiculous," Trump told the hosts of "Fox and Friends." "I mean what was he doing with Lee Harvey Oswald, shortly before the death? Before the shooting? It's horrible."

In July, on the morning after he accepted the GOP nomination, Trump revived it in response to Cruz's refusal to endorse him during a prime-time convention speech days earlier.

Heidi Cruz

After a super PAC shared an old image of Melania Trump in a provocative pose, the candidate went nuclear -- against Cruz's wife, Heidi.

First, he tweeted a cryptic threat, saying: "Lyin' Ted Cruz just used a picture of Melania from a G.Q. shoot in his ad. Be careful, Lyin' Ted, or I will spill the beans on your wife!"

And a day later he retweeted a supporter who posted an unflattering image of Heidi Cruz.

Carly Fiorina

This one was folded into a long Rolling Stone feature published in September.

Here is how writer Paul Solotaroff described Trump , as he watched cable news and saw Fiorina:

"When the anchor throws to Carly Fiorina for her reaction to Trump's momentum, Trump's expression sours in schoolboy disgust as the camera bores in on Fiorina. 'Look at that face!' he cries. 'Would anyone vote for that? Can you imagine that, the face of our next president?!' The laughter grows halting and faint behind him. 'I mean, she's a woman, and I'm not s'posedta say bad things, but really, folks, come on. Are we serious?'"

Ben Carson

They are allies now, but when Carson was threatening to overtake him before the Iowa caucuses, Trump compared the retired neurosurgeon to a child molester.

"It's in (Carson's book) that he's got a pathological temper," he said on "Erin Burnett OutFront." "That's a big problem because you don't cure that ... as an example: child molesting. You don't cure these people. You don't cure a child molester. There's no cure for it. Pathological, there's no cure for that."

Sen. John McCain

More than a year ago, Trump leveled one of his first and most infamous snubs . It happened on a Saturday during an event in Ames, Iowa.

"He's not a war hero," Trump said of John McCain, who had spent more than five years as a prisoner in North Vietnam. "He was a war hero because he was captured. I like people that weren't captured."

McCain, a Navy pilot whose fighter jet was shot down, was tortured during his imprisonment and spent years in solitary confinement -- and refused early release when the North Vietnamese learned his father was a Navy admiral.

John Kasich's eating habits

It's true that conspicuous (food) consumption had become a theme of the latter stages Kasich's campaign. But Trump really lit into the Ohio governor, who did not, for a variety of reasons, end up attending the GOP convention in Cleveland.

"Did you see him? He has a news conference, all the time when he's eating. I have never seen a human being eat in such a disgusting fashion," Trump said during an April rally in Rhode Island. "This guy takes a pancake and he's shoving it in his mouth. It's disgusting ... Do you want that for your president? I don't think so."

Past primary foes: Lindsey Graham, Jeb Bush, Marco Rubio, Rick Perry

Graham: Trump called him an "idiot" and gave out the South Carolina senator's personal phone number at a rally.

Trump called him an "idiot" and gave out the South Carolina senator's personal phone number at a rally. Bush: The "low energy" jab was delivered again and again to devastating effect, but don't forget Trump bringing mom Barbara into the mix. "Just watched Jeb's ad where he desperately needed mommy to help him," Trump tweeted in January. "Jeb -- mom can't help you with ISIS, the Chinese or with Putin."

The "low energy" jab was delivered again and again to devastating effect, but don't forget Trump bringing mom Barbara into the mix. "Just watched Jeb's ad where he desperately needed mommy to help him," Trump tweeted in January. "Jeb -- mom can't help you with ISIS, the Chinese or with Putin." Rubio: Often derided as "Little Marco," a comment on the Florida senator's height. Trump also said of Rubio at an event in February, "I have never seen a human being sweat like this man sweats." He then sprayed out the contents of a water bottle to make his point, a reference to Rubio's infamous water break during his State of the Union response in 2013.

Often derided as "Little Marco," a comment on the Florida senator's height. Trump also said of Rubio at an event in February, "I have never seen a human being sweat like this man sweats." He then sprayed out the contents of a water bottle to make his point, a reference to Rubio's infamous water break during his State of the Union response in 2013. Perry: Tweeting last July, Trump said Perry "failed on the border" and "should be forced to take an IQ test before being allowed to enter the GOP debate." (Note: Maybe Trump has already made amends with the former Texas governor, as Perry emerged an a ally after leaving the primary.)

The media!

Just kidding. But if he did, it might take a while.