A selection of shower water heaters. Note the plethora of knobs and dials.
One thing which I find a cumbersome and irritating chore day-in and day-out is having to fuss with the mechanism in my shower for getting the water to come out hot. Even though I have a new water heater and not some antique system, I still have to go through a process every night where I turn a crank about 10 times while holding down a big, plastic button that I have to twist to a certain setting. Doing this while crouching, naked, and cold is the worst part, especially when it doesn't work on the first attempt and takes twice as long to get going. Wait, no, the worst part is that in the summer water is too hot even on the lowest setting as water comes out of the tap so warm that minimal heating is too much (and no heating leaves the water too cold).
I won't miss the cumbersome and troublesome water heating method that I've been using in Japan.