I do know (personal experience) that some applications refuse to work properly if you don't grant them every bit of access they request. Even if that access is not fundamental to the operation of the application.

The example I speak of is Digsby. I saw some of my friends had postings from Digsby on their wall, with "achievements" like sending 100,000 messages etc. I didn't want that, so when I installed Digsby I unchecked that option. Consequence: Digsby would randomly boot me out of Facebook Chat and not allow me to log back in. I had to remove it from my Facebook apps list, re-login, and turn off wall postings within the Digsby app itself rather than Facebook's permission management.

That's the kind of thing that irritates me.