I think dinnerladies is underrated. Its the sort of show that you can watch again and again and its still funny. Its a shame they didnt make more episodes than they did. It deserves more credit than it got.
Trollied is also underrated. No one seems to have watched it, but its really good.
I feel like not enough people have watched True Detective. Its HBO though and I suppose thats what you get, although GoT has no problems pulling viewers in.
Under the Dome, only one of my friends had heard of the TV series and it was criticised for being very different to the book but it was really exciting and I can't wait for the second series
In The Flesh. Currently on iPlayer at the moment, second series is starting in a few weeks. Definitely recommend! My friend had to basically force me to watching it last year and I'm so glad she did. D: