Responsibility "Gene"

Why are certain people able to set clear boundaries and only take on the duties, tasks, and burdens that are truly theirs, while others feel compelled to step in and make sure things "turn out right?"

Is the latter a case of overresponsibility and what are the consequences of such actions? Are these people ripe for manipulation by those looking to move some responsibility off of their own plates? The latter often commit to performing a task and then blatantly ignore it. Are they just ambitious overreachers who we should cut slack since they have the big vision, or are they trading in the plaudits that come with signing up, knowing that when the rubber meets the road, one of those overresponsible types will jump into the breach to help them?

Can you stand by and watch something important you are associated with (like a presentation, a client meeting, or a planned family event) come to a disastorous end because the person responsible did not do his or her job? I have trouble not pitching in to make it better. Am I a team player, an enabler, or someone who likes the role of martyr? These are questions I have to ask myself.

I would appreciate any feedback, as I currently have run into this dilemma several times in the past couple of months. I do know that such overresponsible behavior seems to carry with it a simmering resentment, at least for me, that can't really be good for me or those I work with.