Sliding Doors is about the two different paths that Gwenneth's life could have taken--1) if she'd caught a train and 2) if she hadn't. It's an interesting film about the tiny decisions in our lives, and the things that seem like disasters but aren't and vice-a-versa.
I emailed my husband and asked (jokingly) if he thought it was a sign. He replied, "That we should move to Britain and miss a train?" Har, har.