Just simply amazing how Steve Moffat and his wife are getting away with it: words that would be censored in most series, fly about in this one and you don't feel offended. Every episode is different and the build-up (flash forwards, split screens, themes that run through various episodes) is amazing for a comedy series. British humor at it's very best and very recognizable for every modern day couple. Don't hesitate to go out and buy the four series, you will not regret it and they will put a smile on your face over and over again.