This post is in the spirit of this fun one. I spent two nights in a hotel in beautiful Malaga (ES), and was confronted with these 'interesting' controls:
Here's the equipment:
Both rotating knobs have a small unmarked button on them, which can be pushed in, then comes back out by itself immediately. I was not able to figure out what either of those buttons did.
The left knob is marked with temperatures from 20C to 50C, so purportedly controls temperature, but there's no mark anywhere around it to act as a pointer, letting the user know which temperature is selected. Not that it matters much, I've tried spinning it in both directions, with and without holding the button, and never felt the temperature change from "warmish". It spins much more easily in one direction than the other, leading me to believe the direction with the most resistance must be doing something.
The right knob selects the flow and function (showerhead, telephone-style showerhead, bathtub spigot, those 3 body jets on top, and the 4 jets below those [which I never managed to turn on]), by turning in one direction, which you can do if the flow is on high. Keep turning (harder) when the flow is on high and it will switch functions (yes, think about it). The functions are marked 'T', 'C', 'C', 'L', 'E' (how clear!), I don't know in which language those letters might stand for something. The button apparently does nothing. Since switching functions can only happen by spinning one way, if you miss the one you wanted, you have to go through the whole array once more, spraying water out of every one of those holes.
WORST. SHOWER. CONTROLS. EVER.