There are a lot of anger-inducing things in PS2 TBH - dying when its seems lag is to blame, losing a MAX or vehicle through what feels like no fault of your own, stupid TKs, etc. etc. but the thing that probably makes me the angriest is rezzing a bunch of people as a medic and then, when I die, nobody returning the favour
Still, overall I agree with KesTro - I don't really ragequit PS2, I generally just log off when I can't find a fun fight any more. Honestly that's the key to me playing the game at all - if I can find fun, balanced fights I'll keep playing for hours - if it's all just us camping them or them camping us, or ghost-capping, then I'm out.