With timeA concept which is related to our perception of reality; that part of existence which is measured in seconds, minutes, hours, days, weeks, etc. expressionA word or group of words used in a particular situation. E.g.: Good morning, at six, on the sofas like always, constantly, continually, all the time, the past continuous can express frequently repeated past actionA general term expressing that somebody or something does somethings which annoy(ed) the speaker:

She was always teasing me.
They were constantly arguing about money.
He was continually interrupting me.
I was getting into trouble all the time.
He was always calling me at night to ask me how I was.

These sentences imply that the actions happened very often, but they are not meant literally. To express the literal meaning, the past simple is used:

He always called me at night to ask me how I was. (He called me every night to ask me how I was.)

Diagrams

Past continuous for developing states
Past continuous Past continuous for temporary past habits