8. Touch Screen
Despite being written during a time when most house phones still had a turn dial, a passage in the book that describes Zaphod struggling to tune a radio on his stolen spaceship, The Heart of Gold. The futuristic controls described sound remarkably similar to a modern reader as "the controls were made touch-sensitive--you merely had to brush the panels with your fingers".
Not satisfied with touchscreen however, Adams then moves on to casually dabble in gesture control, suggesting that "now all you had to do was wave your hand in the general direction of the components and hope. It saved a lot of muscular expenditure, of course, but meant that you had to sit infuriatingly still if you wanted to keep listening to the same program".
Sounds about right.