A shower with traditional knobs, and a sensor of some kind. The first time you use it, you set the temperature/pressure with the knobs. After that: You step in,

A shower with traditional knobs, and a sensor of some kind. The first time you use it, you set the temperature/pressure with the knobs. After that: You step in, the shower detects you, and automatically uses your previous temperature/pressure. The sensor could use facial recognition, or a footprint scanner, or a fingerprint scanner, etc.