Another dumb idea I had by thinking about Overcooked
In between serving people you have to wash dishes/wipe the service counter by swiping the lockdown bar. If you don't clean, you get lower food reviews and the health inspector is summoned faster (see my previous post re: health inspectors). It's something silly to do, makes use of the touch screen, and it's fun to watch people struggle as they move their hands around the cabinet.
Or if you're a super serious player who hates fun, you let everything be dirty and it makes the game more challenging.