For me it varies. On leisure rides I find I'm switching PAS levels and gears to find the level of exertion I'm looking for, based on where I'm riding.
For "task-oriented" riding in the city (errands, commuting etc.), I stay in high gear, and tweak the PAS based on traffic.
Forget gearing down at a red light. Waste of time, energy, (and cassette) I say.
I find it much easier and faster to get that initial boost by nudging the throttle while pedaling up to my cruising speed. It's my impression that car drivers also appreciate this.
It's a LOT easier to be assertive of your space, but not outright aggressive, especially in situations where the bike lanes are full of Uber/Lyft jerks, reducing traffic to a single lane.
That's just my experience, here in Toronto.