How do people tear shower curtains?

Because I’m poor, I’ve spent most of the 30 years of my adult life living with a succession of roommates. Almost without fail, the shower curtain ends up looking like it’s been attacked by feral cats. Usually the grommets at the top are ripped out, leaving the curtain dangling by successively fewer and fewer hooks. I don’t understand it. I’ve never torn a shower curtain. I’ve tried asking them how they manage to tear it, and none of them ever admits to noticing. I am baffled by this. How are they managing to do this, and why is it almost universal? Are they swinging on it like monkeys? How can they not know how they’re doing it?

Shower curtains are not expensive, it’s not something which outrages me. I’m just curious about the phenomenon. Does this happen to any of you? Do any of you tear shower curtains? Does anyone else have this experience where everyone else in the world seems to spend their time gnawing on shower curtains like crazed wolverines?