I was a VERY small kid in junior high, weighing in at about 65lbs. I wasn't an athletic person in any way, and had absolutely no interest in proving this little fact. One day he approached me and asked me to join the team mid-season. His goal was to have a default win in my weight class because precious few other teams had someone as small as me... so when I walked out to meet my match, I'd never meet anyone, and would always have a default win. No problem.
I agreed to join on this basis... and made it very clear that I had no interest in actually wrestling anyone, which he didn't complain about. I went to one practice (where I got my ass kicked) and then went to the first competition. He walked into the warmup room after checking out the opposing team and gave me a "you're really going to have to do this" look. He gave me the option of forfeiting the match, since I definitely wasn't prepared for this... but all the looks at the other team members convinced me that I might as well try. We all knew I'd undoubtedly lose, but it was better to lose fighting than to lose by backing down... a sentiment I still think I feel the same about. I went out and met my match, and of course lost it after being in the ring for about 15 (10?) seconds.
The next morning I thought about it and decided that this wasn't what I'd signed up for, and I didn't want to do it. I went to him before school and gave back my uniform and told him I was quitting. He tried talking to me about it, then tried guilting me about it, then tried yelling at me about what a pathetic loser/quitter I was. I took it, because he was my teacher and someone I should listen to, and in the end still just walked away. He never really interacted with me the same way again.
In retrospect, it was more his issue than it was mine, though I don't presume to know what the issue was. I bought in based on what I was told, and what I was told wasn't the reality... so I walked away from false advertising. I don't know if he was trying to compensate for his presumed-failure son (who also quit the team), or from no longer having someone in the 65lb weight class, or from some vicarious need, or what... but in his eyes, what I wanted or felt was irrelevant. It didn't matter that the only reason I joined was as a favor to him, or that he didn't deliver on his pitch.
In retrospect, I don't need to feel guilty about this. It's not my fault. It's not something I need think about or worry about. It bears no reflection upon me (as I was just being who I am, rather than who someone else wanted me to be), and walking away doesn't make me a bad person. I guess in this realization, more than anything else I feel bad for him and his situation that made him need this, and for the other people that I can imagine he might have pushed things like this on to. Mind you, they're not my responsibility either, but I recognize the situation and sympathize with them.