For the uninitiated “Pugging” is related to the acronym “PUG” which stands for “Pick-up Groups”. “Pugging” is essentially putting together a group of players to do some sort of group content that you don’t normally play with or even know. World of Warcraft has several ingame tools to facilitate this, including a queue system to automatically build groups for 5-man dungeons or PvP battlegrounds and a group listing for other kinds of group content.
I take advantage of these tools fairly often, because I don’t have it in me to try and put together groups without them (I remember the days when they didn’t exist and you had to stand around in a city advertising yourself to find a group) and my friends don’t always happen to be playing at the same time that I am for whatever reason. And I usually have positive experiences, far more than the negative. Most people, I find, just want to get through the content as quickly and efficiently as possible, and they’re forgiving of mistakes if you’re willing to admit them. Sure, there’s plenty of assholes who are not, but I’ve found those to be the exception rather than the rule.
As far as the relatively recent addition of LFR raiding, yeah, okay, that one’s easier to be a big ol’ clusterf$ck and more people does mean a higher chance of dealing with a big ol batch of assholes, but I will always be fond of LFR because during the time when I wasn’t part of a raid team (most of Cataclysm and 2/3rds of MoP) the LFR difficulty let me see that raiding content, something I will always be greatful to it for. Now that I’m a part of an amazing raid team, I usually don’t bother doing LFR without them, but it’s damn nice that it exists.
So yeah, being the introvert that I am, I usually enjoy the pugging experience.