I hate to break it too you but movies are ment to be entertaining, if it isn't entertaining it fails to meet its most basic criteria
whats the difference though?
Transformers vs Godfather, why is Godfather better? What would you rather watch? I would rather watch Transformers cause I think it is far better, quality of movie cumulates in the fact that the movie is a solid watch to, I could just put transformers in at any time, with Godfather you have to dedicate a night, and then it becomes less entertainment, and more so film homework so "film snobs" will think I am on top of my game.
A book can be well written and feature some of the most boring literature ever assembled, the same can be said for a movie, I'm not saying the godfathers are bad, I think they are pretty cool in context, but I think movies like Transformers and what not are far superior
even with all that said, all "good" is, is personal preference, nothing more nothing less, you can say the directing was good, but again it is your opinion that the directing is good