Back in Pennsylvania, "seasonal" food generally meant having to find creative ways to use zucchini, canning tomatoes (which you wouldn't want to eat later but couldn't let go to waste), and apple butter. There's nothing I hated worse than seeing grocery bag-size sacks of zucchini abandoned on our table when friends and relatives found their garden's bounty exceeded their ability to process them.
In retrospect, I have to wonder if they were growing them just to find out exactly how many hundreds my mother would gratefully accept before eventually crying "uncle". Maybe they were taking bets on how many of those green nightmares she'd take before eventually refusing. Perhaps they believed we'd learn some sort of magical all zucchini menu and then they wouldn't have to try so hard to fob those things off on us anymore. At any rate, I hate zucchini now, thanks to the excessive quantities my mother tried to stuff down our gobs during our formative years.
When I was younger, "seasonal food" also meant the "Tasty-Freeze" (a run-down "Dairy Queen" type of place) was either opening for the summer or closing for the winter. As a kid, the opening as summer approached always filled me with excitement and the closing was lamentable both because it meant not more soft serve ice cream and school was starting again. In fact, this was the only seasonal food that really mattered to me as a child. The rest of it was just a burden of boring food and time spent trying to preserve it which made it even more unpalatable.
In Japan, students seem relatively obsessed with seasonal food. If a student says his or her favorite season is autumn and you ask why, the student will always say that it's because the food is so good. When you ask what food is best, they tend to be a bit lost for an answer though apples sometimes come up. Personally, I'm always happy to see the influx of food being sold using sweet potatoes and chestnuts. Though such items are available year-round, the variety and quantity tend to increase as the weather gets cooler.
One point that brought this to mind today was the presence of a variety of Japanese doughnuts that I'd never seen before in the bins at a local market. One of them is sweet potato and the other is chestnut. I haven't tried them out yet but I'm pretty sure they'll be good by my standards. I'm one of those people who doesn't like incredibly sweet pastries and am more enamored of getting the right texture than a lot of sugar. In fact, this is probably one of the reasons I'm drawn to food made with sweet potatoes and chestnuts. They always have a good density and high moisture content.
For the most part, I haven't noticed an over-abundance of certain foods being laid on people's doorsteps in Tokyo with a few exceptions. One of them is persimmons which seem to grow unbidden everywhere. Before our landlord tore down and re-built his house, he used to have a persimmon tree and gave us some. I believe that was actually the first time I'd eaten a persimmon and I rather like them though my husband doesn't care for them.
The other item which is often more plentiful than one grower can consume is mikan, though they're more of a winter thing than an autumn one. Mikan are a small Japanese orange which resemble mandarin oranges in appearance but are sweeter and juicier. Fortunately, no one has yet offered either of these items to us at the same rate or in the same volume as the zucchini we were plied with in Pennsylvania so I can still enjoy them.