In general, yes or no questions and answers are fine. If you're asking one, it means that you don't need more information-either it's unnecessary (if I invited you to play golf and you say no, I don't really need to know why), or I can figure out the rest (if I ask my dad if he remembered his clubs, if he says yes I know I don't need an extra set, if he says no I know to go get a second set).
Even in situations where I ask a yes or no, and you feel like there's something both relevant and important to add, you can state it (in the first example-I ask you to play golf, you say no. You then add you're meeting up with some friends at the bar, and ask me if I want to come. I asked a yes/no question, you responded yes/no, then added your own relevant stuff).
Your English teacher was being hyperbolic, and they might be needed in an argument (sometimes they aren't), but in general conversation yes/no questions and answers are perfectly acceptable and common.