Sometimes, when it comes to being helpful, I seem to have the timing of a 17-year cicada. I'll be around, but on MY schedule! I'm the one who's likely to offer to wash someone's dishes as they dry off the last plate. I'd show up when someone's moving and all of the things they can have other people move is already moved, so they say "Well, no, I need to take care of that stuff myself so that's OK, I don't need your help," and I can go off and do something else.
The result? I can get the glowing personal satisfaction of knowing I was willing to help, without the effort of actually helping.
I used to be worse about this; then I recognized the pattern and realized it was like I was subconsciously planning for that to happen. And I do think I'm helpful...generally. I like being helpful. (Heck, I think I'm good at it. Four years ago I temped for three weeks at a Wells Fargo records office. That was an especially busy and productive three weeks, to the point where I literally had about one hour on the clock where I didn't have anything I could do, and I felt really at loose ends during that one hour. One hour out of 120. I was overachieving!)
At times I slip back towards that pattern. (It sort of happened last week, is all I'll say, so that's why it's on my mind.) And it's worse 'cause it's only occasional, and I'll realize what I'm doing, and feel less-than-good about it, and thus think to myself Dude, don't, and even if you can't be helpful that way you can be useful another way, OK? So maybe I've trained myself out of that pattern, or at least the fake-positive-reinforcement part of it. I may have tricked myself out of it! Like breaking an addiction!
To sum up, I know I can't do everything, but I like doing.