Here is a task in an English test:
Last night my neighbors got angry because I (played / was playing) the piano. They repeatedly came to my door and knocked, but I didn't hear the knocks. Why? Because I (played / was playing) the piano.
I was taught that I should choose the simple tense to talk about habits or routines, and the continuous tense to talk about being in the very process of doing something, but that doesn't really help make the choices in this particular task. The sentences are neither about a habit nor about any particular moment of time. What's more confusing is that two choices have to be made, which suggests that the answers might be different.
So which choices should I make and why?