I to always click no, if I've been doing something with them, whether we have talked or not, and they seem to be respectful of me and understanding of the game, I typically say yes, and in some cases propose the friendship myself
I havn't had any one throw a temper tantrum like that with me yet lol but I have had some little boys try to start following me everywhere I go, a couple actually were already on my friendslist(probably from my first couple days playing I suspect) , they are no longer on my friends list lol.