Some phones are great at this - if you're on a call and want to look up your account number to give to a service rep, getting close enough to tap an app button

Some phones are great at this - if you're on a call and want to look up your account number to give to a service rep, getting close enough to tap an app button turns off your screen, even in speakerphone mode. Pull back your hand to tap the power button to turn on the screen? Well the screen detected your finger left and turned on just as you were hitting it. Now you're in a third state, intentionally off screen, and just moving your finger around the sensors won't change that. You have to tap the same power button again, and then start the process all over. Don't forget you've been talking to a service rep this whole time, or more likely sitting going "uhhhhhhmmm..." like a dipshit.