The only time I use facebook:

For some reason my Nexus One comes pre-installed with Facebook and it can't be uninstalled without rooting (which for laziness sake I don't want to do). I don't have a Facebook account. The Facebook app periodically tries to authenticate and obviously can't. Instead of gracefully giving up (or allowing me to uninstall) it brings a Facebook login page to the foreground.

So every day, two to three times a day, I have to exit out of Facebook which has given itself focus. To me this defines the Facebook experience and their focus on quality software.

I dislike Facebook not for all their privacy concerns (which are annoying), but because I was always genuinely frustrated using the site.