It ... depends what content you're doing.

While you're still going through the MSQ, the likelihood of finding a jerk is almost zero.
If you're trying to do Extreme/Savage, *especially* if you are in no way ready for Extreme/Savage, you'll find some angry people.
Areas that attract 100+ people in the same shout channel will have at least one jerk spamming it, guaranteed: Hunts, Bozja, the Limsa Aetheryte.
And PvP and RP attract the same types of problem players they can everywhere else.

All that said, it still *is* by and large a very open and friendly community. At least compared to the alternatives.