People will probably hate me since I caught my Feebas on the third square I tried and immediately caught five more.
Golbat are more annoying than Zubat because of Mean Look/Confuse Ray. Tentacool/Wingull are very annoying out on the water, especially since the encounter rates seem to be jacked up out there or something. When using the Rusturf Tunnel, Whismur are very annoying too, because they're the ONLY THING IN THERE. I like Exploud, but. Come on.
I find Oddish very annoying. Why? Because I wander through the Safari Zone frequently and I'm not always paying attention, so sometimes I'll hit A before going to run on it and catch it. I've gotten five Oddishes this way. It's irritating. Pidgeys and Rattatas are everywhere in RBYGSC, but I never paid them much attention because they're easy to flee from.
The stupid Shuppets on Mt. Pyre are annoying too. The encounter rate is WAY up there and they seem to be the only things in the actual tower. It's very irritating when you're trying to get all the good items in the tower.