Only one thing bugged me

The fact that Walter and Phyllis were planning to commit the murder so soon after taking out the policy on her husband. As was mentioned in the film, only two weeks had passed between the enactment of the policy and the "accident", and even this was delayed by Dietrichson having broken his leg. I know they were eager to get him out of the way, but it is only logical to assume that the insurance company would raise an enormous red flag in such a circumstance. Furthermore, so much is made about Walter's inside knowledge of the insurance business that it seemed out of character for him to not even suggest that they wait several months.

But aside from that, an absolutely perfect film.