You people are all weird. Showers are time I enjoy spending.
It's the drying up that I need to optimize, and that's not dependent on how long I was in the shower.
Drying optimization: Leave the bathroom door open and the shower curtain partway pulled so humidity doesn't collect in the room. Have an oversized bath sheet in reach (you can get good ones at Costco). When you're done showering, towel-dry hair, then the rest of you, then comb your hair so it doesn't stick. Without humidity in the room, you don't keep sweating so you don't feel clammy. You can get dressed immediately if you're pressed for time. If you're like me and hate putting dry clothes on damp skin, find something you can do for ~15 minutes at the com...
Inspired by recent batch of productivity posts, I wrote my short story down. To a reasonable extent, this story is real.