hmm... never clogged up a toilet, never had one back up on me or overflow either...
but there was one time... I was in a play, and went to the bathroom about half an hour before "everybody onstage" time (which is about an hour and a half before showtime) I flushed, and the stupid toilet just didn't stop flushing! Some people do makeup or hairspray in the bathroom, so it was full of people. They laughed at me, and then, one by one, they'd go find friends and say, "hey, man, you gotta come see this! Ella flushed the toilet, and it just keeps going! Someone just walked into the crowded green room and said, "Ella broke the toliet." so soon, there's a whole crowd around the toilet. Luckily, everything had already gone down. We had no idea what to do, so we just left it. Someone even went in it while it was flushing because there were no other toilets available.
We went back after the show, and the stupid posessed toilet was still flushing. I have no idea what was up with it. By the next morning, it had quit.