One reason - alcohol. I have seen people who were scared out of their wits to dance - even an idiot-proof dance like the macarana - get on a table after three good shots of Jack Daniels whiskey and pretend that they are competing in a nation-wide dance competition. And in answer to your next and inevitable question - no, I have never done that myself. Acted foolish at times, but never got up on a table. The only other reason that a person would do that - On a dare from their friends (even then, usually alcohol is involved). - A girl wants to make her boyfriend jealous by showing that other men would notice her (again, alcohol helps a lot)

Thank you, Salam! Your answer is witty!

cause they don't have chairs !!

Fdmaxey! Пригласите меня на бал! Я люблю танцевать вальс!