Haven't gone to a movie theatre without having a choice in mind.
However, there was a time when I wasn't preoccupied on a Saturday afternoon of watching sports when I would run through the cable movie channels and catch a movie there. Usually, I have already missed some portion of the movie but begin watching and get engrossed by the story. I know I found Rounders
this way, plus Mystery Science Theater 3000: The Movie, Boiler Room, Catch Me if You Can,
this way. All great movies by my opinion and usually not the type of movie that I will run to the theatres to 'must see.'
It can be so frustrating trying to figure out some of the early details or reasons for relationships until you get a chance again to see it repeat through on Cinemax or Showtime for another showing that day or the next.