I do really think it is a bad thing , the only thing I can think of that may make it bad is having a lot of angry tension built up while you are sleeping and not getting a good night sleep.Other than that I don't think there is anything wrong.z
Oh! I always used to get told that!! My parents always said it cuz the bible says "do not let the sun go down on your anger". Which basically means it's better to let it go.
its not, but it is at the same time because it may be hard to fall asleep if you are in a bad mood nd you may not be able to stop thinking about the situation.
Because it lets the anger stew and get worse. It's better to talk to whoever you're angry with ASAP or otherwise deal with it.
its not really, maybe you could end up having a bad dream in result of it but its nothing bad bad