And all the early 70s music used - perhaps surprisingly in some cases. Tracks from Cream, The Who and T. Rex were always going to sound good. What's more surprising is how awesome the series manages to make Paul McCartney, Mott The Hoople and Lindesfarne sound. Special mention also to the eponymous Bowie track that soundtracks Sam's first moments in '73. And has a pretty awesome reprise when Sam throws himself from a roof to return there in the last episode.
Don't know if the DVD I have is different to the series which I didn't watch when it was on television, but the song where Sam throws himself off the roof in the version I have is Over the Rainbow by Israel "IZ" Kamakawiwoʻole. Still pretty awesome though.
Over the Rainbow sounds in the previous scene, once Sam is back in 2006. His suicide is set to Life on Mars.
Ho Yay / Foe Yay: Gene loves bringing up how much of a fairy Sam is, but he sure likes to get in his personal space. In this◊ Radio Times cover, they don't even look like they're fighting. They're just really close.
Iron Woobie: Sam Tyler. He's a Fish Out of Temporal Water experiencing tons of angst (and Sanity Slippage) as he tries to get back to his own time, and he gets verbally, physically and sexually assaulted on a regular basis. He's also a Badass police officer who manages to make the most out of his admittedly sucky situation.
Gene Hunt is the quintessential jerkass and bad cop. But in Series 1, Episode 2, when he tries to frame Kim Trent to stop him committing further crimes, and Sam insists on letting Trent go due to lack of real evidence, Kim Trent eventually goes on to commit another armed robbery and attempted murder.
Though at the same time, whilst Sam sticks to his principles and ends up being right much of the time, he sometimes comes across as this. Played straight in Series 1 Episode 3, where all the evidence points to Ted Bannister as the murderer despite Sam's misgivings. It turns out he was right, and the victim really died due to an industrial accident with a drive belt that snapped.
Memetic Mutation: A Running Gag in the fandom is to jokingly claim that Sam Tyler is The Master who forgot who he was (either due to another fob-watch incident or through some other form of amnesia) and is now stuck in the 70s.
Misaimed Fandom: Gene Hunt was initially portrayed as being nothing but the "overweight, over-the-hill, nicotine-stained, borderline alcoholic homophobe" that Sam Tyler described him as. Although the writers had always intended to deepen Hunt's character as the show went on, they were disturbed at the way that Hunt's extreme political incorrectness actually made him very popular with fans.
Strawman Has a Point: Frank Morgan. He's right — Gene Hunt is a flawed police officer. His motives may be right, but his judgment is skewed. He is far too emotional and violent. The fact that he put himself at the front of his suicide mission does not negate his flaws, or the fact that he put his team in danger when cooler heads could have completed the task with less risk.
Gene Hunt himself in the second episode (see Jerkass Has a Point above). Technically Hunt should not be framing Kim Trent, but at least it would have kept him off the streets.
What Could Have Been: It was originally going to cut to black, series over, but the writers decided to give the viewers a bone and let them see him rejoin his friends in 1973.
Other endings that were considered: Sam waking up in 2006; Sam staying in 2006 but using things he'd learned in 1973; Gene somehow ending up in 2006 with Sam whether in his imagimation or as a legit "time traveller"; Sam finding an old Annie in 2006.