My kids got me a 365-day sailing knowlege calendar for Christmas. So every day I get to test myself. One of the questions was, "According to the Coast Guard, what percentage of recreational boaters have a rudimentary understanding of the rules of the road?" Answer? Ten percent.
I was depressed. Always assume the other guy a) doesn't see you, or b) thinks he's the stand-on vessel. Sort of like riding a motorcycle....
So be one of those 10 percent - take at least a boating safety course!