I hate all of them, so let me explain why.
CAMPERS
I hate them. So much that when they start to get to me, I invite my friend to play and we both euip our SPAS-12s and mess him up, then spin around while crouching. It likes like your iceskating on them, and it's way more awesome than teabagging.
N00BTUBERS
These are ridiculous. Do you suck so much you have to launch a high propelled grenade? Really? Especially where I'm trying to capture the headquarters? Really? Just die by my claymore or go up and stab me like everyone else.
SECOND CHANCE
I really don't mind this, since I usually shoot them enough to kill them. But, when I don't I equip my Makarov Dual Wield, go into cover. The jump out and empty it on him just for equipping that perk. I suggest you do the same.