I was also recently surprised by the number of otherwise reasonable friends I have who are just completely unaware of life outside of SOMA and the Mission. I've had a lot of people tell me that they didn't know where the Inner Sunset was located. If they can't walk there in 15 minutes or get there by BART from the Mission stations, it doesn't exist.
Public service announcement to 20-something SF newbs: there is life outside of the Mission and SOMA, kids. The rent's cheaper, too.
Muni needs to reduce the number of stops a bus/train makes.
Aside from bart or muni in the tunnel, I found the fastest public transportation in SF was the various limited or express buses that go from the richmond to downtown. They make very few stops and move quickly.
The thing is, the express buses can easily pass the slower regular bus that make every stop. That wouldn't be possible with the streetcars, which I think would have to be all or nothing.