This disorder is typically more common in males. It is caused by the short
person's feelings that
society looks down on them for being
short. Characteristics include, in any combination, talking loud, bringing other people down, excessive pride/cockiness, and sometimes (my personal favorite) climbing on tall objects, all in a futile attempt to feel bigger. Utterly hilarious to the average-sized onlooker.
Closely related to fat people syndrome
John: OMFG I AM LIKE THE COOLEST
KID EVER!!!
Susan: (to Brian) Wow he is that
kid?
Brian: Haha that's John. He suffers from short people syndrome and has to talk loud and cocky to feel bigger.
Susan: Oh my gosh wow look at him now he's climbing that
tree hahahaha