You wouldn't think something as small and mundane as a stamp would be much cause for controversy, but over the years, there are quite a few stamps that have upset more than just collectors. Here are 10 of them.

1. In 1994, the U.S. Postal Service somehow thought it would be a great idea to issue mushroom cloud stamps to honor the 50th anniversary of the end of WWII. Naturally, the Japanese government wasn't thrilled about the notion. The White House stepped in and basically vetoed the idea (the New York Times reported that the then-White House Chief of Staff "made it clear that President Clinton preferred an alternative"), so a depiction of Harry Truman was used instead.

2. Apparently 1994 was a rough year for the Postal Service - it was then that they released a stamp to honor rodeo star Bill Pickett. Bill was in the 101 Ranch Wild West Show and toured with Buffalo Bill, Will Rogers and Tom Mix, among others, and his stamp was part of a "Legends of the West" series. The problem? The 20 million sheets of stamps that were shipped out for sale at post offices had the wrong guy on them. The stamp actually depicted Bill's brother, Ben, who was noticeably more rotund than Bill. The Postal Service recalled the stamps and had them destroyed, but not before one post office accidentally sold three or four sheets before the official release date. To be fair, it was an honest mistake "“ the caption of the picture used to create the stamp was mislabeled. However, if you find one of these stamps, it's not worth the chunk of change you might think. The Postal Service took 150,000 of the sheets with the errors on them and issued them by lottery, making them not quite as unique. They go for anywhere from $175 to $275 on the market today.

3. The Bureau of Engraving and Printing has regulations that stop their engravers from putting anything unauthorized on stamps, even microscopic things invisible to the naked eye. But that doesn't always mean that employees abide by those rules.

In 1987, it was discovered that Kenneth Kipperman hid a Star of David in the portrait on a $1 stamp, educator Bernard Revel. The object itself wasn't questionable, as Revel was Jewish, but the whole situation became even stranger when Kipperman was arrested for threatening to bomb the site of the Holocaust Memorial Museum in D.C. He was protesting the destruction of the current building to make way for the Holocaust Museum, which happened to be right next door to the Bureau of Engraving and Printing. Since then, supplies of the stamp have run out, and rather than reprint, the Postal Service has decided to replace it with a portrait of Johns Hopkins.

4. Stamps.com used to let you put anything you want on a stamp "“ almost. The Smoking Gun put the company to the test and submitted pictures of Ethel and Julius Rosenberg, Monica Lewinsky's dress, Slobodan Milosevic, Jimmy Hoffa, Linda Tripp and the Unabomber. Well, high school and college pictures of Ted Kaczynski. The typical grizzled, bearded picture we have all seen a million times didn't make it through the censors. Also denied: Lee Harvey Oswald and Salvatore (Sammy Bull) Gravano. Perhaps because of the experiment, Stamps.com changed their policy and decided to no longer allow pictures of adults or teens, unless submitted through "trusted channels" such as portrait studios. Photo from The Smoking Gun.

5. Russian stamps issued in 2002 caused quite the stir among citizens. The stamps honor six of Stalin's secret policemen renowned for their abilities to catch foreign spies, but at least two of those six also committed terrible atrocities against their own countrymen, including deporting thousands of peasants in the "˜30s. Although the Russian House of Stamps issued a statement saying they were strictly honoring the 80th anniversary of Russia's counter-intelligence service, citizens were concerned that the government was trying to send a message.

6. A similar situation (being honored for one cause, while angering citizens for other reasons) has recently arisen in Britain, where a stamp has been issued with the picture of Marie Stopes. She was a pioneer in the field of family planning who opened the U.K.'s first family planning clinic, which is why she earned a spot on a stamp. But she was also a Nazi sympathizer who sent a book of poetry to Hitler and was a fan of eugenics. Despite the controversy, Stopes remains in the set of stamps that honor women (so far).

7. A 1999 U.K. stamp featuring Freddie Mercury upset a lot of people "“ but not people opposed to Mercury's lifestyle, as you might suspect. Well, the Royal Mail received a few complaints regarding that, but the majority of them were upset because Queen drummer Roger Taylor was featured rather vaguely in the background of the stamp. The problem? Living people aren't supposed to be on stamps (except members of the Royal Family). The Royal Mail admitted that it was rare that they would break the rules like that, but basically said that given the size of the stamp, a person featured in the background really shouldn't be that big of a deal.

8. Famous Bluesman Robert Johnson was at the center of controversy in 1994, 56 years after his death. There are only two known photographs of Johnson (and a third much-disputed one), so when one of them was altered for the stamp, people were upset. Namely, smokers. The famous photobooth picture of Johnson, with a cigarette dangling between his lips and a guitar in his hand, was changed to delete the cigarette. The President of the National Smokers Alliance called the omission "an affront to the more than 50 million Americans who choose to smoke." However, a cig has cameoed on a stamp before "“ a 1982 stamp featuring FDR shows him holding a cigarette and holder.

9. Earlier this year, a collector discovered that one of the Postal Service stamps featuring an American flag had 14 stripes on it. The Postal Service apologized and said that the extra stripe at the bottom was added to give the flag definition and the mistake was never caught. They have no plans to recall the stamp, but did release a statement saying they acknowledged the error and apologized for it.

10. When the U.S. issued a stamp to honor Frida Kahlo, not everyone was happy about it. Especially Jesse Helms. He took to the Senate floor to protest the stamp, saying she was an unfit subject. He wasn't the only one: people wrote in, upset that a Communist, drug addict and bisexual should be featured on a U.S. stamp. Even the Wall Street Journal published an article called "The Stalinist and the Stamp: The Wonders of Postal Diversity."