It is also considered very stylish to leave the neon-colored "tall" sticker on the shirt, so that everyone knows you didnt wash it first.
ALSO, if the beltloops of your pants show below the bottom of your tall tee, for instance around your ankles, you are totally badass.
This fashion trend originated many years ago in the poorer black neighborhoods, where families could not afford to buy new clothes, therefore younger kids wound up wearing clothes which no longer fit their older siblings and/or parents. Being several sizes too large, the shirts often reached the wearer's knees.
One of many current fashion trends derived from practices of lower-class memebers of society used several decades ago.
guy 2: No man, i ain't got no cash for a new shirt, so i wear my dad's old one even though it looks like a woman's nightgown on me!