Hot Take: Your estimated time to arrive at a destination on the Google maps app is just the app challenging you to a time trial race.

And I almost always win

You can always win by going on foot because of the usual lack of footpaths on Google Maps.

follow up: and it's designed to always show a little longer than you'd actually need to, so you arrive on time more often, so you always have the feeling of "having gotten through well" - and don't get all road ragey because you're going to be late.