Near the end of the fourth episode of The Supersizers Go in which the food time travellers go to the 1970s, Sue Perkins says that she saw the '70s through the banisters of the staircase, as she and her siblings peered downstairs at the goings on of the adults. This was how I experienced a good chunk of the '70s too. I used to peer through the treads of the very '60s open wooden staircase in the house my parents rented in Wokingham, Berkshire, head upside down, spying on my parents and their guests when they entertained.
In any case, the '70s episode was a lot more entertaining than I thought it would be, purely for the nostalgia value. I kept on squealing in recognition at many of the various foods trotted out. It did help that I actually spend a few years in the '70s living in England with my family, since the Supersizers focused naturally on a very British version of that decade.