[header] How to say no [title] Understand when to say no. [step] Two-year-olds are famous for saying " no " like it's going out of style, because they've only recently learned that such a thing is possible, and the new chances for independence it provides are fun and exciting. Two-year-olds are also known for being selfish and thoughtless. 
However, they're on to something: it's okay to say no. What separates adult usage of the word is that we can learn when it's appropriate and when it isn't.