Pharo shower panel SkyLine leverage knob.

thingiverse

I only upload this because of how well it worked out. If you look at the included photo you can see that the shower control knob is as smooth as they could make it. It has become more difficult to turn over time. So with wet soapy hands it is near impossible to turn for me and pure impossible to turn for my wife. It has to be one of the worst design ideas I have seen in a while. So this object is my solution and it works ridiculously well. No screws or glue needed. It just slides on and fits snugly into place. Just in case you are wondering, yes, I am still trying to figure out how to remove the handle to properly fix it. But for now this baby works great.