Foul throws. Either enforce them all or scrap them completely. I speak from a position of acute trauma - we had a teacher when I was a kid who hated football and took his revenge by making the foul throw his major issue as a reluctant referee, claiming that pretty much any kind of throw was a foul throw, to the point where none of us wanted to take a throw-in, and if forced to we'd just stand there, paralysed with fear. It made us all go off and study the rules with an intensity unknown in other areas of learning. So even now I notice every single one of them with painful clarity. But refs only seem to blow when they're bored, because they know that otherwise it would happen too often. So stop it!
