First of all, when I'm cruising a narrow lake w/out a rider and another boat with a rider is coming at me, I almost always stop my boat to let them pass to minimize my wake.
I was out this weekend, taking my parents out for a cruise while they were in town and a boat w/rider came up behind me and passed (I didn't stop), then pulled right in front of me (putting the rider too close to my boat for comfort). I wasn't really bothered by them pulling in front of me but what did bug me was when the rider fell and I was passing him giving him the peace sign, he was frantically waving his arms with a frown on his face as if to say that I should stop my boat and wait for him to get back up and then follow (or he was saying I had been following too close which would have been the fault of his driver that pulled in front of me).
Anyway, I often do stop my boat when a good rider goes down in front of me to wait for him/her to get back up and enjoy the smooth water but I didn't in this case because of the lack of courtesy from the other driver.
Right or wrong? Either way I was bothered by the immature reaction from the rider when I was waving a peace sign... as if my stopping was his right.