This is what happened.

In order to improve performance issue(Customer complained), I changed the code.

In order to make sure the good quality, I tested dynamically adding/deleting the records to see how it behaves ( Should be like before --- No crashing).

But he didn't understand it and thought it has nothing to do with issue the customer reported.

He tried to blame me and make my life miserable, like --- Do you understand that?

Is that a sentence a manager should be using???