I have a short list of TV series that were cancelled that I think should not have been:
There were others, but I cannot think of them right now.
- Surface - From a couple of years ago. It ended after first season and the ending left viewers with a lot of unanswered questions! Good writing, good story, good acting... There's actually a huge petition online to bring it back...
Daybreak - Broadcast ended 2/3 way through the season, but you could at least watch the end online
Bionic Woman - I think the writer's strike killed this one. I thought it was decent enough.
There were others, but I cannot think of them right now.


