No matter how many sincere apologies you make to someone who you have said something rude to or have treated badly, you can never erase the feeling that you gave this person by your words and your actions. It is almost impossible.
Oh, they may truly forgive you, and try their best to get past your transgression, but there is something deep down in their soul that will never quite forget how you made them feel.
It is for this reason that you need to carefully consider your words and your actions. Don't think that you can simply do whatever you want to and say that you are sorry later - life doesn't work that way.