I've seen parts of both Garfield movies, and used to be a fan of the strip. From what I remember, the strip constantly breaks the fourth wall; it's natural for it to break it again in the movies. Plus, it's a kids movie, so expect a certian level of cheesiness.

I've heard rumors that the Garfield movies were produced to be mediocre, and it does a fair job at that... just like the strips. It's bland, common, and I wouldn't be suprized if you muted Garfield the movie would become better.