the bad thing: the quizzes. I swear that every other notification on my home page is "Janet Jones* took the 'Which 80s pop star are you?' quiz and the result is: You are Lamahl"... or similar. No-one cares.
the good thing: hiding people's status updates. Ideal if you're going to come into contact with someone on a day-to-day basis (and so deleting them / ignoring their friend request is going to be a bit awkward) but know that they're going to be clogging your facebook with "Janet Jones is wondering what to have 4 lunch lol x" every ten minutes.
(names were changed to protect the identity of those involved)