It’s easy to think “it’s just a few minutes.” But as the number of people that you hold up increases, the true cost of being late scales rapidly. Being 10 mins late to a meeting with 10 others is 100 minutes. Holding the door for 20s on a train of 600 people is over 3 hours of time collectively. Unless your time is worth a lot more than everyone else’s it’s worth thinking twice before holding the door to a train or not taking the start of a meeting seriously. I think, at the end of the day, it’s really about respect.