Suppose you’re working with a “day can” (small container for a particular job) of a solvent. It’s properly labeled and you even remembered to get a lid for it so you don’t spill any taking it to and from the work location.
This job involves brushing some solvent onto mating surfaces, then wiping them clean. The subsequent tasks take about 10 minutes, and then you’re ready for the next pair of mating surfaces. Your foreman walks by and asks you why the lid is off the can.