I have been in the shoes of the "n00b" that needs to "L2P" many times. Very little grouping, very few instances, so basically I was always under geared and never knew strategies (reading things on the net is usually not enough, and anyway doesn't compare with real experience). Most of the time people would just behave like jerks, really not friendly or helpful at all. So actually I stopped grouping all together. That made end-game content rather empty to me, and that's what got me into multiboxing.

That's actually one of the reasons why I love multiboxing : If I fail, it's my fault, I can blame nobody else for it, and nobody else is going to blame me for it. I only play alone, with real life friends, or with people I have known basically from release and who didn't forget it's a game

It is interesting to see that all the PUG invitations on the trade channel (which is already annoying) seem to ask for people who already know the encounters and already have the gear. Hhuu ...

Now, it is true that lack of focus tends to drop DPS. I can run an Heroic Utgarde Keep in 45 minutes without one character dying when I'm focus, or in 1h30 with several wipes when I'm busy doing other things at the same time. I guess in a raid it must be very noticeable too.