Unnecessrialy complex fuel system, leaving the pilot to do what the aircraft system should do automatically by design.
Unreliable gauges and low level alarms routinely crying WOLF
Pump switches out of view
All waiting for innocent error and then, GOTCHA!
Pilot victim of booby trap, yet blamed.
Thank goodness my fuel gravity from two tanks,on-off, but gotcha flap switch detents back to 'up'