These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
For the series:
Nightmare Fuel: The BBC put up one of the first ever content warnings before an episode of Quatermass II. Nigel Kneale once said in an interview he didn't want kids to watch the stories.
Special Effects Failure: Watch for the control rod attached to the rocket at the end of Quatermass II. Other than that, there aren't any to speak of, which is pretty remarkable. Even the monster at the climax of the original serial, which was just a glove puppet stuck through a photograph of Westminster Abbey's interior, is quite unsettling judging by the surviving photographs of the effect.
For the band:
Awesome Music: Quatermass as a whole qualifies, but particularly "Post War, Saturday Echo" and "Laughin' Tackle".
Most Annoying Sound: The various electronic instruments heard in "Punting"— a huge part of its Ear Worm qualities. And they just won't go away.
Nightmare Fuel: Quatermass... is not a happy album, as can be gleaned from the tropes described thus far. The long and short of it is, don't listen to it late at night. It'll haunt you.
Some Anvils Need to Be Dropped: "Post War, Saturday Echo". Aside from the obvious anti-materialistic statements, the title evokes the sort of comparatively trivial societal plagues that were non-issues to those living in wartime, but which have come to flourish in peacetime. Roger Waters would, presumably, very much approve.
They Changed It, Now It Sucks: The 2013 reissue. The biggest deal-breaker is the incomprehensible placement of "One Blind Mice" as the opening track. There's also the remix; while the sound is largely improved, many songs often have sections that are borderline unrecognizable as a result, and the instruments don't coalesce like they should. Some also complain about some songs being split up, and others, combined. Oh, and one of the pteranodons is green now.