Nothing lit up the internet this week quite like hand holding, or the lack of it.

President Donald Trump reached for Melania Trump's hand on Tuesday. She seemed to pull it away to brush her hair aside instead.

Being the second time this week the first lady was on video appearing to avoid that powerful hand, it kicked off a flurry of amateur analysis and internet jokes, plus a not-so-veiled trolling of the Trumps in the form of a photo of the Obamas blissfully holding hands, posted online by former White House photographer Pete Souza.

As someone who is only lukewarm on hand holding, (the literal warmness of the hands being part of my problem) who has occasionally avoided it even with people I really like (go-to moves: hand in the pocket, phone in the hand), I watched the three second clip wondering if it was really that big a deal.

Does hand rejection really signal romantic rejection? Or is it more a personal preference that happens to involve your partner, like sleeping with the fan on high or eating a ton of garlic?

I found some couples happily holding hands and asked them why they were doing it, which is one of those things that seems obvious until you actually have to answer. Along Beach Drive, St. Petersburg's hand-holdiest of sidewalks, couples were not prepared to answer this question.

"I have never actually thought about it, ever," said Dave McPhilmy, 46, of Syracuse.

"It's automatic. We just do it," said his girlfriend, Megan Smith, 35.

The vast majority of people who walked by were not holding hands, of course. They might have been couples, or friends, or siblings, or maybe they were just walking the same direction and didn't even know each other — how was anyone supposed to know if they weren't holding hands? That question that wasn't lost on a young couple out there doing some serious, white-knuckle gripping.

"It means that no one else can look at him the way I look at him, and no one's allowed to talk to him except me," said Jill Kilgroe, 16.

"I think it means love?," said her boyfriend Jack Hosack, sheepishly looking over to gauge her reaction (she grinned shyly and looked at her feet).

Both agreed that by high school, holding hands was not the big deal it had been a few years earlier, so I turned to my 14-year-old sister for the middle school perspective. Graduating 8th grader Sophia Spata was, by far, the most certain person I talked to.

"It's not a big deal like it was in sixth grade, but everyone knows it's what you're supposed to do," she said. "If people are officially going out, and they don't hold hands, people are going to be like, 'Why aren't they holding hands?' And if we see someone holding hands who is not officially going out, we're all like 'Whaaat?'."

In my casual research, I got back no great arguments for why holding hands is so great — some like it, some tolerate it — but I did get lots of Seinfeld-esque observations.

In brief: interlocking fingers are a must, because non-interlocked fingers feel wrong and parental. Mixed-hand-holding-preference relationships are a struggle. If one person likes it and the other doesn't, it's hard to make it work. Crowded sidewalks are a no-no. Holding pinkies is a fun alternative if you've got sweaty hands. Holding hands is better when you're dressed up.

Some women said holding hands is too intimate for a first date, even if a kiss isn't out of the question.

"Walking around holding hands all over the place feels like a bigger deal," Shannon Kelly, 26, said.

"You don't do that with someone if you're not emotionally in it," Laura Burnes, 32, said. "It's actually more intimate."

One half of a hand-holding couple I met on the sidewalk said her boyfriend didn't hold hands if his friends were around, or they were near his job, because he didn't want to seem "whipped." He didn't deny it.

Jeanne Grinstead, a former editor for the Times, who for years had been seen walking into work hand-in-hand with her husband who still works here, said that after decades together, holding hands remains a "simple but powerful statement that someone's got your back."

People tend to not hold hands if they're mad at each other, which might actually be counter-intuitive.

Tampa-based couples therapist Ana Aluisy tells couples working through major issues, even infidelity, to force a physical connection by holding hands, even if they don't feel like it, rather than hoping a physical connection will return after they've talked through their problems. She assigns hand holding as "homework."

The stakes of public hand holding can be high. A gay couple in the Netherlands was attacked last month while walking hand-in-hand. That led to another, viral hand holding story as straight Dutch men started holding hands in solidarity with them.

Closer to home, Joe Massiwer, a restaurant manager in Tampa, never holds hands with his boyfriend in public because "it's just easier than feeling all that hatred."

In the '60s, the Beatles wanted to hold your hand, but didn't really get deep into why. Shakespeare had Romeo and Juliet drone on about hand holding in a way that rings false at best, and creepily obsessive at worst. Romeo calls Juliet's hand a "holy shrine."

Archaeologists in Italy not long ago unearthed a Roman couple who'd been holding hands since the 5th century, and even more recently a couple was excavated from a grave beneath a chapel in England after 700 years with fingers intertwined.

I couldn't ask them if hand holding was a big deal in their day, because they're skeletons, but most modern folks would agree that 700 to 1,500 years is too long to hold hands, especially since studies suggest it only takes 20 seconds of contact for the body to release oxytocin, sometimes called "the love hormone," which may play a role in relaxation, trust and psychological stability.

We choose the hands as a point of contact, rather than say, pushing our elbows together, because they're packed with more sensory neurons than most spots on the body, essentially the lips of your arms.

Think hand holding isn't a big deal? Straight men hold hands in some other countries as a sign of respect. But try asking a hetero American of the same sex to hold hands with you. Exactly.

That's why a photo of President George W. Bush doing just that with a Saudi prince in 2005 drew so many immature giggles back home. That was the last presidential hand hold to really make headlines before this week.

But so far, we've only learned what happens when you do hold hands. What about when you don't? Like most negative propositions, that's harder to interrogate.

Unless you're the president. Then we know exactly. It becomes an internet sensation.