When I started driving I had an issue with the GPS on my phone. It was a shitty deal. I realized, after a few days, I knew my way around the different neighborhoods but could not always connect them. I am super competitive and hated not having the best way to go. I also am stubborn. So, when my GPS did work and I didn't agree with the route I went my own way. This did not always work out great for me or my riders. So, I started trusting the GPS.
SF is basically two grids that intersect at Market street. The area where they connect means you get bendy roads. The hills mean your view is never more than a mile. These two features coming together make for cutty routes.
What I mean is that there are some super money routes which are very counterintuitive, at least for me. This is what a day on the road looks like:
Drive like that for a few days and you will gain some perspective.