Yeah, you'll find lots of posts on here about similar stuff. We all deal with it, and it's been very loudly argued with Blizz but they still love it.

Best thing you can do is laugh at their ignorance. On the time thing they're just making a math error. They did a Time X 5 rather than the appropriate Time / 5, easy mistake to make. Generally the best answer to this is (if they're level 50+) "So what's your /played time?", then tell them what yours is divided by 5. I've had people log off after that conversation (Personally I'm level 63 with less than 2 days time in each).

BG's... only join with friends until you get really good at it, pugs are very intolerant.

And once you're 60+ you can just hide in instances all the time like I do. Now that I'm doing Coilfang I often stop off outside SSC to put on a show for my guildies who are raiding, and pickup some water, wish em the best then dive in.