People make mistakes. Sometimes they are huge mistakes, very difficult to recover from, some are just stupid things, easy to get over. But really, there is little we cannot be forgiven for and even less we cannot afford to forgive.
Yes, someone may make you angry but what do you have to gain by being angry? High blood pressure, stress, and disappointment will follow. In the long run, it serves no purpose.
There are numerous forgiveness days (which we probably need). Today is actually on the National Level. (considered National Forgiveness Day). Global Forgiveness Day however, falls on August 27th, and Internationl Forgiveness Day is the first Sunday in August.
So if not today, pick one of any of those days and start forgiving those who you feel have wronged you. It will certainly help them but it may even help you even more. The grudge you hold is actually harder on you than it is for the person you are holding the grudge against.
How to celebrate – Remember you may need some forgiving one day so find someone that has wronged you and forgive them, making sure they know you have done so. Find someone you have wronged and ask forgiveness from them. Forgive yourself of things you know you have done wrong.