Unless of course you have to sit down to pee.
I sit down to pee and I have broken many heads over the years.
I got started on this sitting down thing after peeing on my floor a time or two at 3 am in a sleepy stupor. This is only at home though. try it some time. It is a lot easier and safer.
Seriously though, some seem to break easier than others. I have only shattered one and that was a bang dark matter. It just blew apart. They will all wear down over time.