I'm on Blackhand and dual boxed for a couple of years but no one really even notices that. Hell I dual boxed instances and they just thought we were friends.

Once I did the 5 Shammy I got hit with a wall of what you're describing. My skin is growing thicker but still I generally try to hide when going to town now. I logoff in some building that people don't normally have a reason to go to. I hide 4 in an alleyway and just run in my main to buy/sell, etc. just so I don't have to deal.

And.... if it's /say I don't even pay attention anymore, unless I just want to chuckle. If they /tell then I'll chat with the interested and refer the angry to blizz.