Romantic comedies, of a certain type at least, are often criticized for being predictable. Such criticisms miss the point altogether; in fact, the more predictable the storyline, the more true to form. The whole point of the genre is to be as predictable as possible (not in its hypotheses but in the resolution) but still be entertaining. How else could one create something to be enjoyed over and over?
Of course the predictability is of a rather specialized kind, more common to music, and it is more a matter of seeming completely predictable due to graceful artistry with the conventions.
The just released The Proposal, starring Sandra Bullock and Ryan Reynolds, is an excellent example of the genre.
