I have read many blogs discussing the issue of whenever you should forgive or not, this subject has been widely discussed. I believe that people SHOULD forgive usually. However, not to forgive really fast all the time.
Forgiveness helps you to feel better.
Basically, when you forgive someone you think that it will make just the other side feel better. However, you don't know that it will help you a lot to feel way better as well. When forgiving, you simply 'trick' your brain to stop being mad on the other side which disappointed you or made you become angry. It is not so easy because the process of forgiveness means to stop being angry and to respect/feel happy with the other side.
For example, someone you know talked to you not nicely and made you upset with him/her. That way you will feel like you will never forgive that person who hurt you. But if you make that "change" and decide to forgive the other side then you will feel way better because you know that you did the right thing.
Forgiveness is must in order to build a good connection
When forgiving someone you and that person will have a better connection between each other because forgiveness helps to understand the mistake of the other side.
Let's take for couples, for example. Couples always fight each other but only those who know how to forgive the other side will be able to build a better communication and a stronger relationship.
Why should you not forgive too fast?
Forgiving too fast sometimes can be the opposite of building because the other side won't have enough time to think of his/her mistake. That way the whole situation will happen again and again. You should remember not to forgive too fast and to show the other side that what it did hurt you.
I strongly believe that forgiving people is a must do thing, it helps to understand the other side and fix bad behaviors of people. On the other hand, you should not forgive too fast because letting the wrong side think about its mistake in behavior is a good thing.