I've only ever been impressed with mass transit in megacities like NYC. SF public transit left a lot to be desired. The muni was not worth the hassle and I did not have a bart station near my rented room in a house.
Yeah, the USA has terrible mass transit, except in a few cities. Many other places around the world do much better.
A few years ago I was in Honolulu, and wow is it crazy to have a gajillion cars on a tiny island (separated from any other possible destination by thousands of miles of ocean) all stuck in bumper-to-bumper traffic every day.
I used to avoid the Bay Area's buses like the plague for many years, but in the last couple of years I came to ride them a lot and have been pleasantly surprised.
They're really convenient, with buses being able to take me to within a five to ten minute walk from most anywhere within the Bay Area that I want to go, and even closer within SF proper. They're a lot quieter than the BART (where I feel I need ear plugs to protect my hearing), it's as clean or cleaner, and there are now apps like Citymapper which tell you exactly which bus to take and when to get where you're going.
My main gripe is that a couple of times buses just didn't show up at all when they were scheduled to arrive (not just late, but just skipped a bus).
NYC's subway system is definitely way better than BART in terms of having way more stops and going virtually everywhere, but it also has its own problems (like the stops being deadly hot in the summer and freezing cold in the winter).
A few years ago I was in Honolulu, and wow is it crazy to have a gajillion cars on a tiny island (separated from any other possible destination by thousands of miles of ocean) all stuck in bumper-to-bumper traffic every day.