In my opinion, it's the hardcore crowd that are the worst. My worst experience was with a tank who refused to do a WP run with me simply because I was a DRG AND I was under-geared. He said "You might be able to run it in 20 minutes, more likely 30" and left the party instantly. Despite the fact that I was running WP in 20 minutes with full AF/lvl50 gear and am now clocking a consistent 15 minute run with a static which has dropped down to 10 minutes since we added a BLM.

They rely too much on gear and class to measure players. I feel like casuals are more laid back, willing to give people a chance, and willing to admit when they've made a mistake. I've done Chimera, Hydra, Ifrit, and Garuda in one shot with casual groups; and the Chimera battle I did with 3 healers LOL.