At this rate we might become competent
As I just said to someone via IM: I'm not sure if concert shooting is fun in spite of, or because of, the crappy conditions. The showier performers are constantly in motion. The lighting is either spectacular or terrible, depending on the half-second; low ambient light combined with frequent bright flashes mean you're waiting for those magic moments when light, motion, and melody sync together.
The burn rate of digital photos at concerts is horrendously high. I started shooting concerts because they forced me to think outside my careful-composition box: shoot, shoot, keep trying, trust that you're going to delete 90-95% of what you take but you won't get that magic photo without trying.
Sorting through the mass of photos the next day is depressing. So many missed moments -- when the lights were in the wrong place or the performer moved the wrong way or a mic stand was in the way -- but it's worth it for the deep, quiet pleasure you get when you see the photos that got it absolutely right.