leaf to hold it all together
Not really. The flavor of the leave is mild but helps your taste bud and eases the spiciness as well.
As the GP said, real Thai food has strong balance; however, it also depends on where you get the food. Each region has different preferable taste. Normally, Northern part tends to be mild to medium spicy hot, Eastern part is medium to hot, the Central part is mild, and the Southern part is medium to very hot.
I guess it is the reputation that Thai food has to associate with peanuts and/or coconut. This is NOT TRUE especially peanut. Most Thai dish does not contain peanuts. Many does not contain coconut and peanuts. I guess the reputation comes from curry dishes (most of them contain coconut but not all types). For peanuts, I guess it is from Pad Thai (but I never order it with peanuts). By the way, Sriracha is NOT a traditional seasoning in Thai but rather a brand name of hot source that makes its name to the west. They don't usually use it in Thailand.
"krueng therm" (literally "engine fillup")
a better literal translation of "khrueang toem" is "additional ingredient"
I had trouble for a while trying to figure out the word "Krueng therm." As the parent post said, "Krueng" can be "engine" or "ingredient," but using the word alone will not give you a clear meaning like that! In Thai, the word does not have a complete meaning until you put it in a context. However, it gives you a sense of something that usually has more than one thing involved, and the word is a noun. The word "therm" or "toem," if I guess correctly, means to fill or to add. However, no Thai people would ever use these 2 words together. Thai people either use "Krueng Proong Ros" ("Proong Ros" means to season food) in a formal way. As you see, the word "Krueng" is in there to indicate the word as a noun. Or another word that Thai people would use is "Puang Prick." The first word means a bunch of (normally you would see 4 different kinds of seasoning). The second word means chilli (which indicates some if not all of them contains chilli as an ingredient). I know that some Westerners would want to make fun of the word, so go ahead. If you don't know, the "F" word in English is actually a type of vegetable in Thai, so go figure.