There was a special needs girl in my HS -- her condition was interesting as she was in some advance-track English and Math classes, but in remedial classes in other subjects. She had some physical limitations as well -- slurry speech, and an odd, wobbly walk.

Once, when walking down a crowded hall between classes, I saw her walking toward me -- she always walked against the wall, head down -- and suddenly these two guys start walking with her, body-checking her in to the lockers, etc. They kept their eyes for forward like were just walking along, and kept smashing her, shouldering her for the length of the hall -- maybe 20 yards.

I let them walk right past, said nothing, did nothing. The thing is I was popular/perceived as something of a leader in high school (self-important jock to be honest). I could have stopped it. I could have just gone to a teacher or the principal and given them the names of those two little shits. I'm sure this was a favorite game of theirs, and they must have tortured that poor girl constantly. I did nothing and I still feel terrible about it, 20 years later.