Spicy
It was an uneventful day at Diego Garcia when Ratchet asked Sam to pause his videogame and explain the concept of spicy food to him, and, as they had nothing better to do, all of the other Autobots turned to listen to Sam's answer.
"Um," he started intelligently, trying to figure out where the question had come from, "Well, it's food that's hot, not temperature hot, but taste hot. It makes your tongue… tingle, I guess."
"According to my research," Ratchet said gruffly, "It is a pain reaction."
He really should have known that the inquiry would be based on something like that.
"Yep," Sam replied, trying to sound unconcerned.
Ratchet's optics narrowed, never a good sign, "So, humans, as if they didn't have enough to be hurt by, deliberately put themselves through pain by eating spicy foods, and they enjoy it?"
Every Autobot waited diligently for Sam to answer.
"You make it sound really bad when you put it that way," Sam quipped, "Listen, it doesn't hurt us, and I promise eating spicy food isn't dangerous. If it was, all chili peppers would be banned, and they aren't."
"Do you eat spicy food, Sam," Sideswipe asked.
"Sometimes," Sam admitted to a decidedly not-pleased Ratchet, "But not often, I don't particularly care for it; mom never let me eat it when I was little and you kind of have to build yourself up to the really spicy stuff. Regardless, it is not dangerous. There's a bigger chance I'll be killed by a bunny than get hurt eating spicy food, a much bigger chance."
"Fine," Ratchet huffed after a moment, "Why, precisely, do humans get a thrill out of riding high-speed death machines known as roller coasters?"
Sam had to fight hard to suppress his groan.