Alright so a little while ago I spent a few months traveling through East Asia. Plenty of sleeping in backpacker hostels and trying not to get hustled on the street and eating weird unidentifiable sh*t off menus I couldn't read. As goes traveling in general, so too goes eating on the road: sometimes it's scary, sometimes it's fantastic, often it's a huge pain in the a**, but the overall experience tends to be enriching and positive and all that crap that means something but sounds mushy when you put it in words.
Surely the most hassle-free way of filling your belly in an unfamiliar place is street food, at least where such a concept exists in any meaningful way. You get to walk up to a stall and point at food that is at the least clearly displayed and often being cooked right in front of you. The transaction is entirely straightforward and the likelihood of getting ripped off slim, since you probably saw what someone paid for the exact same food a second ago.
In the street food category, China beat the hell out of the other countries I spent most of my time, Korea and Japan. Korea has some excellent stuff that I miss, especially tteokbokki (wonderful chewy rice cakes and other less important things in a moderately spicy red "curry" sauce that the Koreans incorrectly think is burn-your-a**-off hot) and gimbap (sort of Korean sushi rolls that are a lot better than that description makes them sound, but are more often sold as fast food in stores than from street stalls). Unfortunately, a lot of the street food is deep-fried something-or-other stuffed with red bean paste and though the variety isn't too shabby, it can't come close to what you can find in China. In any case, banchan, or little side dishes - pretty much always including kimchi - served alongside your other food, are the real fun of eating in Korea.
Japanese street food barely seems like it's trying, even when compared to Korea. In the Kansai region (Osaka and Kyoto and the center of the main island) you can get takoyaki (at its best, bits of octopus suspended in gooey pancake batter with a fried-crispy outer shell - you be the judge) and okonomiyaki (more pancake batter, this time in pancake form and with plenty of bland mayonnaise) and yakisoba (noodles, stir-fried) and whatever-else-yaki. That stuff can be pretty awesome, but it gets old real quick, and then what are you left with? Oh yeah, there's a 7-11 on the corner there, I guess you'll just have to pick up some onigiri (admittedly delicious sticky rice balls filled with something you can't read on the label. Good thing for you this is Japan and everything is color-coded). It's easy to come to the conclusion that street food is too filthy and disorderly for Japan, and maybe that's true. As some sort of consolation, a lot of Japanese fast-food establishments (another area of Japanese cuisine lacking in variety) combine the ubiquitous plastic food items with ticket-vending machines to make for an even more stress-free experience than eating on the street.