The central metaphor running through Mr. & Mrs. Smith is very clever and it compares marriage with being an assassin. There are some really neat scenes that have the leads keeping secrets from each other, but then it goes into action mode and starts slavishly following the classic structure, dropping subplots and characters. Brad and Angelina are great to look at and bring a good sense of humour to the film, but the cleverness slowly drains away as the explosions and body count increases.