Another look back at 1991 - mainly just detail changes in fashion and trains (train carriages since retired), but the scene at the Tokyo Central Post Office shows how it was before e-mail - when people still used stamps for letters, and since they needed to use stamps, they had much more interest in obtaining good-looking ones to use. (If you only send a rare occasional letter, the detail of the stamp design doesn't seem so important).
When the post office released it's special regional stamps, they were sold only in the region being featured at the time, and at the Central Tokyo Post Office, so large numbers of people in Tokyo would go there and buy tremendous amounts of them, particularly businesses and collectors. Businesses simply because it looked better to send letters with interesting stamps, and collectors for obvious reasons. In-between the volume buyers were individuals such as myself buying just a sheet or two.
Here's the link:
Note that there is a bit of traveling about to other places in there, with the post office scenes in the middle.
Lyle (Hiroshi) Saxon