Self fill bathtub? That's a good one. I have a "smart" self-adjusting faucet that can be set directly in temperature.

... but I can't live without a washlet (electronic bidet/toilet). I have come to the conclusion that dry manual wiping is out for me, because in the end it just smears a thin film of shit all over. The washlet is nice - the seat is warmed, water is warmed and it dries me "hands free". It's an amazing yet unassuming robot.