Because they don't know how to express their feeling properly or they are just stupid

I would say because they like you or they really really hate you.

I am quite tall myself but I would love to be short so maybe you could just tell them they don't need to remind themselves they are clumsy by *bullying* other people. I get teased for being tall... But I'm not thaaaaat tall... =D

All you do is pretty much make every person in the group a chance to think of a cool or cute name up and then you all vote for one not knowing whos it is but your not allowed to vote for yourself.

Haha yeah you just buy it