Type of plane
I have a VFR Cessna 150.

Most important control
Radio transmit

Least important control
Pitot heat (if you need it, you shouldn't be flying)

Never working control
Parking brake

Scariest control
Landing light (when it suddenly failed during a night landing)

Control I never use
Transponder test

Control in the wrong place
Fuel shutoff (right where me feet can kick it)

Control I fixate about
Mixture

Control that impresses non-pilot passengers
GPS on button