Snape is ticked off because he can't stand Harry calling him that when he is a teacher, and it's Harry, if it weren't for the fact that LV wants to kill him, Snape proubly would've.
Well perhaps Snape is a coward, because he's always bent to the will of the most powerful, and never standing up for either good or evil. And the reason he's so ticked off is because deep down he knows its true but he doesn't want it to be.
WHAT!!!!???? Oh yeah, he's loved everywhere!*YEAH RIGHT!*
He's smart, but I wouldn't say he has bravery or wisdom, remember when he was going to turn in Sirius and didn't even care about an explaination?