Yes there are a lot of mean people out there, but not everyone is going to shout at you I am very picky about what I pug, I have a (relic) healer and tank but I hardly ever pug as my tank. but i'll happly pug with my healer in the daily roulette or Crystal Tower. Once you get over fear of being new and experiencing dungeons it will become much easier

The Best advise I can give is to find a friendly free company to learn content with.