Being on time is a way of saying thank you for someone’s time before they’ve even given it.

Punctuality is a message about whose hours matter. Arriving late means somebody waits, and waiting is time taken out of their day with nothing in return. Arriving on time says, in advance, that you treated their schedule as real.

Pick the thing you are habitually late for and move your leaving time by ten minutes, not your arriving time. Build in the traffic and the bag you forget. If you are going to be late anyway, send the message early rather than at the moment you were due, since the useful information is time they can still use.