I'm shocked by the reviews I'm reading of this film! I must say, anyone who's ever been in love with someone, particularly if that person is your best friend, in addition to being your worst enemy, this film will SPEAK to you.
I won't lie that this film falls victim to the formulaic conventions of most romatic-comedies, but the screenwriter presents the characters in such a way that you forgive it all. Both of the primary characters are entirely sympathetic in all aspects, even the rich, handsome, bastardly Grant.
At the end, you adore Bullock for much the reason Grant does. Despite her nerosies and non-sense, her heart is in the right place. And while Grant's character is less-sympathetic, you truly regard him as an unwitting villian... one by way of creation, rather than one by way of nature.
Ultimately, it's a story for adults and an adult love... the sort that smacks you in the face, just when you think that you're too old to fall victim to emotion versus rationale. The scene where they pick through one another's lunches speaks volumes to any person who's ever loved someone they hated. How could you love someone who loves beets? Maybe because they love beets when you don't.
I recommend this film highly for anyone looking for a good laugh and sporadic cry on a Friday night. Overall, lovely, brilliant performances... and a script worth lauding, if for nothing else, because it makes such frustrating characters so entirely human.