"Mr. Moony presents his compliments to Professor Snape and begs him to keep his abnormally large nose out of other people's business."
"Mr. Prongs agrees with Mr. Moony, and would like to add that Professor Snape is an ugly git."
"Mr. Padfoot would like to register his astonishment that an idiot like that ever became a professor."
"Mr. Wormtail bids Professor Snape good day, and advises him to wash his hair, the slimeball." -The Prisoner of Azkaban, Ch. 14
This is from when Snape finds Harry wandering in the hallways, and sees the Marauder's Map, but doesn't know what it is. Now, this quote makes me really mad, because I completely disagree with every one of those statements. While he does have an abnormally large nose, it's awesome(and sexy) and has every right to be in other people's business! And he is definitely NOT an ugly git! They're just jealous of how unconventionally sexy he his. Third, he is far from being an idiot! He's obviously such a genius... I mean, he had to be to invent his own freaking spells! And as for his hair, it's not his fault! He just has naturally greasy hair! I'm sure he takes a shower everyday, but there's nothing he can do about it!
It's also sort of sad, because that was the basis of all of Snape's childhood bullying, so I can't even imagine how mad he felt about that.
Also, Harry later finds out that those were the nicknames of his dad and his friends, so how did he not put it together and realize that Snape was teased by James, Sirius, and Lupin? Did he think Snape must have done something to deserve it? Ugh... either way, that makes me mad.