Blackadder and in particular "Blackadder goes Forth" is my all time favourite comedy series. I can watch it over and over again and even quote the lines before the actors do. Favourite line being Baldrick saying "I could go on all night" and Blackadder replying "Not with a bayonet through your neck you couldn't".
All the performances are terrific and each episode is fantastic. I know at the time people were worried about the subject matter. But it was handled with great sensitivity, especially in the last episode.
The previous series had always ended with the death of the entire cast but in a comedic fashion. This was was different. The way each character started to become aware of what was to come and for the first time start to be afraid was just wonderfully done and the closing scene has got to be the best end of any series ever.