Can someone explain how time becomes elastic when you are trying to catch a tram?

The ideal tram to get to work, the one which goes where I want to go, with plenty of space, leaves at 0831. This is exactly one minute into ‘off peak’ times when I’m allowed to carry a bike.

On a good day, I leave the apartment at about ten past eight, and pootle off up the hill in my usual way, coast past the farm, ride across the main road and past the field where they sell Christmas trees earlier each year (October, this time, I expect they’ll reopen in Summer this year), and get to the tram stop at about 0820. Which is fine, except that in winter it is a bit nippy standing on the edge of the fields waiting for a tram to turn up.

So last week I tried an experiment and went a bit later; actually that was less a plan and more because I forgot my keys, lunch and water, and remembered each item after I’d come back from retrieving the last one, but I was able to leave at about 0815. This was okay, because I still had a buffer of 5 minutes, but I decided to to move as quickly as a not particularly fit bloke with asthma can, pushed up the hill, raced past the farm, nipped across the main road between cars and arrived at the station at 0832, to see the tail lights of the tram as it wandered off to Stuttgart…

Explanations please…

[Update: Post finally updated to remove typo that ruined the already feeble punchline. I tried to do this earlier but the WordPress mobile editing page is even worse than the useless ‘Improved’ normal page]