Emma, "silliness" is a tricky word to translate. "Tontería," as you mentioned, might sound slightly off in this context, and "chistoso" is more of an adjective meaning "funny." Sometimes, when translating, it's better to interpret rather than translate literally. For example, you could say: "Mi parte favorita de trabajar con niños es su curiosidad, imaginación y sus ocurrencias." The word "ocurrencias" is used to describe all those unexpected and amusing things kids do that adults find funny. Another option could be: "Lo que más me gusta de trabajar con niños es su curiosidad, imaginación y su forma divertida de ver el mundo." This last one is just an example of how you can approach translation challenges like this. Hope this helps!