Sometimes, as demonstrated by my Mums actions, some fights and harsh words can't be taken back. I honestly believe that all the negative things I hear from my Mum about my Nana, and the negative things I in turn see in my Mum, come from the fact that neither of them could let go of the past and move forward. Due to this fact, they both had very strained relationships with their children. The final moral of this story is to make good use of the time we have with our loved ones. As I found out with my Nanna, even when they look like they are doing well, they can be taken away from you very quickly.
Life is too short to waste on anger and resentment.
If you do, all you end up with is a tone of regret.