This specific Doctor Who story was produced at a very difficult time for the show. The years in between the 1985 hiatus in the sixth doctor era to the cancellation of the show at the end of 1989.
After a mediocre 1st season for the seventh doctor, and the entirety of the sixth doctor era (although he is very underrated), the show started to find its path again in season 25. Remembrance of the Daleks, the premiere episode, was probably better than anything we had seen in 2 seasons. Silver Nemesis, the third story of the season, wasn't very good though. But it was better than anything in season 24. The final story, the Greatest Show in the Galaxy, was a pretty excellent story. And then there was The Happiness Patrol. And let me just say... it is the (second) most underrated serial in the history of the show!
The story has a dark, eerie feel to it. The plot itself is dark. If you aren't happy, you get killed quickly by the happiness patrol. Or get mauled by the leader of the happiness patrol, Helen A's, pet Fifi. Or, of course, there is the Kandy Kitchen where Helen A's psychotic henchman deals with you - The Kandy Man.
list of the special features:
1. Audio Commentary by actors Sophie Aldred (Ace), writer Greame Curry, composer Dominic Glynn and director Chris Clough, moderated by Toby Hadoke.
2. Happiness Will Prevail (23 minutes) - Making of with Cast and Crew.
3. Deleted and Extended Scenes (23 minutes)
4. When Worlds Collide (46 minutes) - Analyizing the stories political ideologies.
5. Photo Gallery (5 minutes)
6. Isolated Music