Childish? Yes it is. (although I think it will work for adults too) 1 out of 10 children also have a certain kind of depression. I talked with a friend of mine with the disease about his feelings and after the discussion I asked him to have a look at the design. I didn´t get an answer. He said: "I have to think it over"
I will post his response a.s.a.p
Btw. The character keeps his smile fixed with a string. So it's not lost forever.