I see there's a lot of hate for poison headcrabs, and I never could understand why. Sure, they bring your health down so that a zombie just needs to fart on you to kill you but usually poison crabs are only ever around other poison crabs. The exception is when you're fighting poison zombies, but those things are slow and then you know exactly where the headcrabs are so they're not much of a problem. Maybe I need to be afraid of spiders, i dunno. I found Striders way more frustrating since they take so long to kill.
Anyway, fuck Cazadors to death. They are evil. Usually the only way I can handle them is if I run like a ***** until there's only one following me, shoot it in the wings or face (unless VATS is being a dick). Remember to pack a stealthboy, children (I miss Threedog).
In fact, anything that has a tendency to swarm can go fuck themselves. Bats, Zubats, Medusas, whatever.
Also, every last boss in every fighting game ever. Yeah, I probably suck at fighting games, I'm not going to deny that. That being said; Seth, Azazel, and Jinpachi Mishima are all assholes. I can't remember a fighting game without a boss that pissed me off. Wait, did Soul Calibur 2 have a last boss? I don't think it did.
I'm clearly missing several.