Voice of Some Experience

I've lived in the USA, Thailand and China. I've visited Indonesia, Mexico, Korea, Taiwan, and Jamaica.

To me, The overall spiciest food I've seen is probably a tie between Sichuan Province, China and Indonesia Hot Pot and Ma Po Do Fu can be very spicy. (the Indonesian red chili sauce is intense but blends well with the rice they cook in coconut milk.)

Indian food and Hunan Province, China food is a very close second and could easily match the top choices in the variation from restaurant to restaurant.

I often have to ask for more chili sauce or ground peppers when eating in Thailand and my Sichuanese wife draws attention from Thai waiters when she shovels four or five spoonfuls of chili sauce or ground peppers on the spiciest preparation the Thais serve.

For people eating "Chinese" in western countries, I politely suggest what you get resembles real Chinese food very little unless you find a Chinese restaurant frequented by almost exclusively Chinese in a major city.

Obviously, I haven't visited some of the other countries, like Malaysia or Sri Lanka, so, like most of those voting here, I can only report on what I've experienced. Korean is a bit spicy but far from extreme, Taiwan is in the same class.

I like Mexican but it's reputation as a "spicy cuisine" is mostly undeserved, given by people from the US whose food is quite bland. It is general knowledge for Asian restaurants that even if westerners "think" they like spicy, they usually don't even understand what real spicy is. I often have to stop my Asian waiter and explain that I am experienced eating Asian spicy before they will serve me their real spicy dishes and I often catch them watching me when I start eating to see if I am able to eat it. It's easier for them to go light on spice for the westerners than have to prepare a meal twice because someone didn't grasp how hot food can be.
P