Running on Michael-time

My husband is notorious for running on his very own time system with a Michael-minute being an undefined unit of time that is always considerably longer than a minute in real time. Sometimes I wonder if he has any concept about measuring time the same way as the rest of us do – or was he absent the day in primary school when they taught about clocks and time? After more than ten years, I have grown used to the fact that 10 Michael-minutes mean anything between 30 minutes and 3 hours but it can be a little frustrating at times.