A hobby of mine is to get annoyed at hand dryers. 80% of the models I find are eyerollingly useless. Blow a faint breeze for five seconds, stop and refuse to trigger again no matter how much you try to slap the air in front of it.
Then there are those 5% that actually gets it. Blowing a jet stream that makes the water droplets sublimate so fast you forget you even washed.
I keep thinking it’d be a good idea to patent a hand dryer that points the detector in one direction and the blower in another, such that to switch it on you have to move your hands out of the air stream, and to switch it off you have to move your hands into it. Your hands get dry not by the blower, but by the action of moving your hands to and fro between the detector and the blower.
Nobody would object or claim prior art because that would put them on record as directly admitting their products are shit.
Then sue everyone whose hand dryers do exactly that. I’d make a killing.