I finally have the name to associate with a type of old-school diner/coffee shop I love so much: googie (here are some photos). I came across it while reading an article in a recent issue of Monocle (the October 2018 issue, which I hadn’t finished reading).
Although it’s a disappearing genre, there’s a bright spot in that the article talks about a resurgence in popularity, in the form of renovation work to classic joints (the article’s focus is on LA, which features them more than the box-like diners we tend to see on the east coast).