They’re cold.  Showering without a door is like showering out in the open air.  It might be great in the middle of the summer, but it’s not so great at 6am, in the Pacific Northwest, in the middle of winter.  You can know that hot air rises without necessarily recognizing that cold air streams in to takes up the empty space.  This cycle provides a continuous cold breeze throughout your shower.

They’re wet.  Yes, of course a shower is wet in the shower, but a shower without a door might be wet all over the place.  It can be surprising to learn how much water bounces off floors, walls, and your body, into unintended areas of the bathroom.  Pay special attention to the use of a shower wand and how a flick of the wrist could send the shower spray across the room!

Potential for water damage.  Water is always tricky to control and predict.  The best way to ensure that over-spray doesn’t cause damage is to waterproof far beyond the shower area.  At a minimum, the waterproofing under the floor and the tile on the walls should extend several feet.  An even better idea is to create a wet-room, where the entire space is impenetrable to water.