I have studied a lot about the past simple and continuous. I know that we use the past simple when we state a fact and that the continuous is used to create the background. My question is I hear that people say "what did you do yesterday" and not "what were you doing yesterday" Therefore, I get that it is more natural to use the past simple. Does is always work like that with other expressions like: last week last year on your holiday?
Is is natural to say what were you doing on your holiday since we ask about something temporary and if the answer is " yes" why it is not natural to ask "what were you doing yesterda"?