While some of the apps I connected to Facebook were legitimate services, like Spotify or Airbnb, a lot of them were dumb one-off quizzes I took years ago. For example, this quiz about a 2009 Miley Cyrus hit.
This app could access my friends list, my status updates, my birthday, photos, and lots of other personal data. Luckily there was a button at the bottom to revoke access.
But be warned: Restricting the app from using your data doesn't mean it's deleted off the app-maker's servers — the exact issue that started the Cambridge Analytica controversy.
More details about the Cambridge Analytica data leak here.