For the past few years I have been increasingly convinced by a single premise. Any movie advertised on the side of a bus is not worth me paying to see.
The first time I realised this was becoming a law was after I had paid to see Indiana Jones and the Crystal Skull. The buses were everywhere, and I thought to start with it was just to mock me. Then it became clear that it wasn't the only film I had no interest in that was on the side of a bus.
These movies seem to come in a few different strands. Children's movies are usually there, so perhaps they are excluded from the quality threshold. 3d movies are always on the buses as well, and I won't pay for them! Rom-coms are always there (Jennifer Aniston will be a frequent star here). Finally the bigger budget ones on buses seem to be the biggest indicator of poorer quality.
This quality rating of film may well just be a local (Leeds) ranking. I am sure my own perceptions of those movies also come into it. After all, maybe you did enjoy 27 Dresses, Streetdance and Angus, Thongs and Snogging. The sources quoted on the reviews will also be notable - Heat, The Sun or Nuts give a different profile of intended audience to The Times.
Hopefully we can put my theory properly to the test...