Answer:
Once upon a time, this person was my sister (and best friend). We have very different personalities and would frequently find ourselves in disagreement. In conflict situations, I would either avoid her or argue with her... and I have come to regret innumerable arguments. One word to describe how I behaved is 'defensively' (and another is probably 'regrettably').
She often behaved rather apologetically afterwards, but during the arguments the best way to describe her behaviour would be 'obdurate'. This of course impeded communication.
I think she would mostly agree. We have passed those times of incessant conflict, but we are also less close than we were then.
Step-by-step explanation: