Yeah sure, they serve as currency when you're stupid/smart enough to forget that they're collectibles and can possibly get you two things out of the vending machine at the same time, but they have the least flattering portrait ever made of Thomas Jefferson on the front. Couple that with the wrenching guilt you feel whenever you run out of cash and are left with only a two dollar bill, and want to spend it, but at the same time know you will be the laughing stock of the town for years to come if you do. It's a lose lose. If you don't spend the bill, TJ wins. He's laughing at you with that smug little "I hate sitting for portraits" grin. If you do spend it, you also fail - at life.
The only way to avoid being in the clutches of an annoying paper icon that really isn't worth much, but that for some reason you think is worth something, is to run whenever you see a two dollar bill. Run faster than Usain Bolt and that guy from the movie who could run faster than a cheetah. Two dollar bills are a plague. You don't want the plague. I don't want the plague...and they certainly don't want the plague. So do us a favor. Don't touch two dollar bills. It's healthier to sniff glue or rub yourself down with pigeons. Just saying.