My old boss told us a story about her honeymoon in Hawaii. She and her husband had gone for dinner to a very nice Asian restaurant. He was mildly congested (allergies, not ill) and when he spotted the wasabi on the table, he said, 'Oh good! This will clear me right up!' and ate a whole large spoonful before she could stop him. She said the results were instantaneous, impressive, and pretty gross. He started sneezing and coughing, and it a few minutes before he could stand up and run to the men's room.
DH has a cousin who is so insecure that he absolutely, positively, cannot admit that he doesn't know something or hasn't done it, and hasn't done it bigger/faster/more than anyone else. This despite the fact that he has lived his whole life in very small towns and has had pretty limited experience with a lot of things. I took him to lunch at an Asian restaurant that featured noodle and rice bowls with varying levels of spice indicated on the menu. One dish had 10 flames (the others were 1-5 flames), a jokey warning ('So hot it burns twice!') and a serious warning about the levels of heat and the kinds of peppers used. When the waitress took our order, she tried to discourage him, repeating the warnings about the heat and telling us that when the chef was making a batch of this sauce, he had to wear goggles and gloves and no one else was allowed in the kitchen. Cousin insisted that he ate hotter food than that every day for lunch, so she brought it out. Yeah. He managed to choke down one or two bites before telling me he was too full. I offered to order him a replacement meal because I did feel sorry for him, but he swore that it was delicious and he just wasn't hungry. He took it home 'for lunch the next day'; it sat in the fridge for a day or two before I finally pitched it.