In my experience it is often inexperienced sailors who don't understand safe sailing that for some reason, think it is up to them to "educate" others. Much of what you learn in sailing classes and reading is not practiced, and for good reason. Can you imagine making a mayday call if someone falls overboard? Yet that is what the RYA course suggests. You should all be busy and there should be no question that you can safely pick them up. If that is not the case, you are unsafe no matter what.

Another common problem comes up when an inexperienced sailor expects the rules of the road to apply where they don't, assumes others will follow them, or misapplies them because of their ignorance or arrogance. I was once sailing with a newby who thought the big ship was going to give way to us because we were under sail :P