When do we ignore the mistakes of others?

When do we ignore the mistakes of others?
That is when we do not want to lose our relationship with that person or we are too fed up with their repeated mistakes.
With the first thing, it's great when we have someone that we want to stick with, want to reconcile to stay together. That relationship leads us to ignore the bad things of one another, accept each other and love each other in peace.
But to the second thing, we are tired of repeating things, which we do not feel comfortable with.
No matter how close they are, but over and over, they keep hurting you. You realize that you ignore their faults not to keep the relationship going, but you ignore them so they can't hurt you any more. You ignore it and you slowly leave them.
One day, they can not hurt you anymore, but actually you have lost a relationship that may have had a very important time for you.
... That's the price you pay for the choise!