Maybe you should.
Every time you give an app permission to access your account, you are also giving permission for that app to not only peruse your account, but they also ping off your account into your friends accounts, regardless of their own set of permissions.
And now there's news on the street that the "Most used Words" Facebook app is causing what is called a "privacy nightmare."
17 million users have started the app and and folks are realizing as they take these dumb ass tests that they are so inclined to enjoy, that they are giving up a ton of personal information to an unknown third party, like their name, sex, friends list, and everything you have ever liked on Facebook. And don't forget, with you having given them permission, they can also access your photos.