Pretty much they are all bad. Out of a roll of 36 I might get 2 "interesting" ones. I keep going over them trying to "find" more that are worthwhile, which is grasping at straws for the most part.
I know right away, just like when you judge someone's face as attractive or not. It only takes a split second.
I often find the ones I had high hopes for are the worst of the lot.