This thread has been a blast to read!
I'm still new (although I've been on for over a year, I have gone months without playing) and I know that I make my share of mistakes but I love being on teams where everyone knows their jobs.
I'm a Blaster (Doc Jupiter) and I know that I'm not a tank. I hang back, pull the stragglers and take out large threats, help tanks and scrappers and keep badguys that break free off of the defenders and controllers.
I think that's the right thing.
I follow directions and will always stick to the plan.
The 2 things that bug me; not getting a sit/rep at the beginning of a mission (not everyone has run that particular mission before and could use the instruction) and waiting for team-members! Gah!!!! I'm married and have a kid. I can be on there for an hour or two but that's it. I'll give it my all for that time, but I don't like to spend it standing around a mission entrance.
Great thread!