Here are some ways to continue not saying what's on your mind:
  1. It's not really my vibe.
  2. It has terrible reviews.
    Because yelp and rotten tomatoes are always right.
  3. It's fine if you're into that sort of thing.
  4. The _________ was nice.
    Ex: In order to draw the conversation away from a restaurant's terrible food, you may want to comment on the tastefulness of the decor.
  5. I wasn't really feeling it.
  6. It's not my favorite but I guess it's okay.
  7. It just doesn't seem very _________.
    Ex: "The story just wasn't believable"
  8. It could have been better.
  9. I don't hate it
    Suggested by @Carly
  10. It's just not my aesthetic.
    I used this a lot in art school during critiques.
    Suggested by @eatthelove