Any time I have a thought of:

I should have done X differently

I’ve been making an effort to reframe the thought as:

If I’m in that situation again, I can do X differently

The former treats the past as wrong on some level, wishing that it had been different. This implies or creates at least a small amount of unhelpful internal resistance or negativity to what is or was.

The latter recognises that the past is always exactly as it ‘should be’. It’s reality. We can’t change it, and we don’t need to. We can always accept it, learn from it, and keep growing.