Sensors fail, causing higher emissions, making the EPA/CARB sad and it chokes the gophers.
WRT people expecting a tip FOR EVERY GD THING THEY USED TO DO AS PART OF THEIR JOB, I sometimes say "You want a tip? Never pet a burning dog" or "Buy low, sell high".
Asking them "Do you think you have exceeded my expectations?" usually takes the wind out of their sails.