In my home town for instance the local operator regularly cancelled buses without notification, ran late all the time and repeatedly made hugely over the top above-inflation/fuel price fluctuation price rises every year. On more than one occasion they cancelled last buses stranding people.
The company would cheat the monitoring of punctuality by having buses wait at certain points along the route (notably the points at which punctuality measures were made) for sometimes 10 - 15 minutes, whereas wherever you actually wanted to catch a bus from you'd often be left waiting 20-30 minutes for a bus to turn up.
The bottom line is, if you want to live there + have any kind of quality of life, you have to own + run a car. Full stop. This is pretty well true for anywhere outside of London (not sure about other major cities, however.)
A lot of the issue is the monopolistic nature of any bus service, and the lack of teeth of the government regulator. Personally I think it ought to be run as a public service with some means of ensuring quality (ok so that's a tough problem :) or at least improve the regulator's ability to fine companies that fail to provide a decent service + have some oversight over (already subsidised!) fares.