Don't go WoW everyone slags everyone off. RIFT on the other hand... unlike WoW trade chat is silent as (on my shard anyway) and other chats their all friendly. Also as long as you play a DPS you can't really go wrong. Tanks and healers get the most **** for messing up.
+1. although healer is a good class to be if you want to play with others, as lots of people like to have extra healers so it's easy to tag along.
anyway i suggest you try each class since it is a good way to learn how to be effective in a group, many just play one type and really have no idea about other classes; which is a shame since to be a good group you really need to understand each class and adapt your playstyle so the group is well balanced. for instance tanks always get the blame even when a noob dps start off full dps and steals the aggro. if the noob had played tank before he would know that a tank need to build and maintain aggro. but a tank doesn't do much dps and must resort to hatred etc... which can be slower to build up than full dps at the start.
i think Age of Conan has a free trial offer up to level 40 so give that a try to see how you like MMO and learn some basics, terminology etc... it's also the best looking MMO, the combat system is cool and it has a lot more content now. too bad many didn't stick with it at first because for the first 6 months it was a bit lacking content wise past lvl 40.
start on PVE servers and dont do PVP, since you will learn the hard way what ganking means and that can be a terminal put off.
unfortunately, as in life, you will always get idiots who are rude so can't really do anything about that other than to ignore. when you meet some people you like, get along with, just play with them and do the group quests together. even if you aren't the best group out there doesn't matter as long as you all have fun, lots of people take the fun out of MMO, looting being the biggest cause of nerd rage

.
plenty of clans always recruit, but that is hit and miss. try out a small clan at first where you know the people and have fun with them. if you become hardcore than you can always join a hardcore clan later on. be warned those usually have requirements from members, and take game very seriously so not really fun, not to mention politics

. but i think it's the only way to do the end game raids since those need well coordinated plans, which are very hard to do in PUGs
good luck and remember to have fun