Life on Mars is one of the shows mentioned in the feature and here's what the BBC had to say that incredibly memorable ending. (Note: It probably doesn't need saying, but if you've still not seen the ending, don't read on!)
After an accident, modern-day detective Sam Tyler (John Simm) woke up in 1973, when men were men, and men were also sexist alcoholics in bad trousers.
Over two series, viewers were left to wonder whether his predicament was real, or a fitful by-product of his coma. In the final episode, Sam learned that corrupt cop Gene Hunt (Philip Glenister) was the "tumour" in his brain. If he could get rid of Hunt, he could go home. The operation (get it?) was nearly over.
Then, he was told the exact opposite: He really was in 1973, and suffering from amnesia after a car crash.
Eventually, the "real" Sam woke up in a hospital in 2006 - but the writers had one final twist in store. He decided he preferred the 70s after all, and jumped off the hospital roof, sending himself back into a coma, and back into the arms of his dream girl, Annie.
The Guardian called it "the perfect finale" but the Express declared the "shaggy dog story" was ultimately "baffling".
Still, it fared better than the short-lived US remake, where Sam turned out to be an astronaut on the first manned mission to Mars, trapped in a malfunctioning hibernation chamber.
But, 6 years on, what do you think of the ending to Life on Mars? Would you have done it differently? Tell us how below.