To me it's foremost a courtesy thing for the smell. Don't be a fucking savage and press the damn timer button before you sit!! When you're done and you rise, if it still stinks hit the timer button for more run time!!
If it's steam then run it til it disapates! No one can use the mirror til the steam is gone! Also the damp environment causes rust, paint peeling or mold on tiles & glass!! Are YOU gonna update / redo the bathroom? No? Then use the fucking tools that are in there for courtesy & pragmatism!!!
Thanks for coming to my TeD talk...

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