I am looking for clarification: can I use "was being" to refer to things that happen in the past? If so, please give example in a sentence.
Yes, you can do this.
Sue was being an idiot.
Now, compare to:
Sue was an idiot
This second example implies that a trait of Sue was her idiocy in the past. The first implies that Sue acted like an idiot for an ongoing period of time in the past.
Most of the time this doesn't matter, and the "was" is preferable to the "was being."
Jack was being an idiot when I dragged him away from the fusebox.
Mark was being a buzzkill when I grabbed the phone from him.
In this case, you need the "was being" because the state/actions associated with the state were ongoing when the interruption happened.
Past Continuous Tense is used when you want to emphasize the development or process of things or things or the time when things or things happen ...
The use of past tense continues Usage Example
Expressing what is happening at a time in the past:
When my sister got there, it was 8 p.m.
Expressing two concurrent actions in the past:
While I was taking a bath, she was using the computer.
While I was driving home, Peter was trying desperately to contact me.
Expressing the action in progress, another action interferes:
I was listening to the news when she phoned.
I was walking in the street when I suddenly fell over.
They were still waiting for the plane when I spoke to them.
Repeated actions in the past and disturbing others:
My mom was always complaining about my room when she got there.
She was always singing all day.