As a long-time healer, I find people understand if my attention isn't on chat when they see that I'm grouped somewhere. Everybody gets that. Even so, I can usually work in a good bit of short-burst conversation between heals. It's socializing on my rogue that frustrates me. I can't seem to keep repositioning and hotkeying and strafing and clicking while keeping up my end of a captivating text chat. First, I fall back into keyboard turning, since my fingers are right there. Then before long, I'm caught in an open line of text, spewing "wwwaaaddssssssssss" at everyone in the guild.
Dead. Fine. Back to my mouse and keybinds -- and radio silence.
Are there characters you avoid playing when you're feeling chatty? If so, is that because you find the mechanics -- either the focus required for gameplay or the actual typing while you play -- to be too twitchy for multitasking? Is your chosen class or preferred keyboard/mouse setup simply too mechanically intensive for you to comfortably divide your attention?