You shouldn't expect people to take short showers.
Steve wants to cut back on the family's water bill during a drought.
Steve wants to save on water.
Steve starts mandating that you turn the water off while brushing your teeth.
Steve limits showers to 4 minutes long to save on water.
Steve's family starts following this rule and saves 5 gallons of water each brush.
Steve's family is furious with Steve regarding that rule.