What is forgiveness? In rudimentary terms, it means accepting that something happened that affected a relationship to salvage that relationship. In reality, it is so much more. Every time you forgive someone it is important to learn the lesson the experience taught you. Never forget what happened.
Now, never forgetting sounds much like holding a grudge. It doesn’t have to be. Let’s use a “basic” example: your friend lied to you to avoid something. A grudge means “I’m never trusting them again”. A well-conceived memory would say “my friend is capable of lying to change their situation, but does not lie often”. This involves a shift in expectations. Rather than being upset, just come to terms with the fact that your friend is willing and able to deceive in certain situations.
Being angry about anything is very draining, both from your energy and overall happiness. Allowing your expectations to mold to the world around you is a very mature way to remain well-adjusted. Politicians lie. If you continue to be surprised by this then you aren’t making the proper adjustments. Friends are there when you need them. If you continue to call someone a friend who is never there for you, then you are leaving yourself wide open to emotional suffering and heartbreak.
The bottom line? Use good and bad events and behaviors to constantly mold your expectations of the world. Be precise, though, just because one person betrays you does not mean everyone will. Keep these ideas in mind, especially going into the holidays where emotions tend to run very deep. Don’t let one lump of coal pollute your entire holiday.