Bravo...
Your integrity earns my utmost respect.
I appreciate all of the replies to my original post. The opinions ranged all the way across the spectrum, from just saying I was right to take the money to saying I should not only give it back, but take the remaining 40 tries (before I started kicking at the ball), shooting straight at the ball, as a continuation of the original bet.
To be honest, I wriggled out of the original bet and wriggled into an altered bet. Kicking the ball into the pocket was clearly not in the "spirit" of the original bet. I do believe that the reason he let me kick at the ball was that he thought he was going to win the $100 anyway, that I wasn't going to make the shot, but that isn't really relevant, is it?
The comments that rang most true and useful to me are the following:
So when I see him next, I plan to give him the money back. I don't want to shoot at the damn shot again as I hurt my back when trying it yesterday. (I'm 67 with a bad back and jacking up on that shot so many times messed up something in my back.)
But what if he refuses to take the money? Then Hu's suggestion that I donate it to some event at the pool hall might help make things right. I'll let you know what happens.
Your integrity earns my utmost respect.