Don't be too rigid. That's the key. Even those who form rigid...they play double standards and that's why you know they have hidden agenda and they are just messed up.
Holding on to pain and being who you are is a choice as you have rightly said. Transfering your pain to make others be like you is even more inhumane. You might be old but that doesn't make you wise. Some people are advanced in age but far from being reasonable...always acting on impulse rather than understand things.