I think most of the time it's better to let it go as long as you're truly letting it go and it doesn't persist.
There's a time, like the book says in "The art of not giving a fuck" to not give a fuck!" But once in awhile, and only you will know - YOU NEED TO ROAR AND YOU NEED TO PUT OTHERS IN THEIR PLACE. For if you don't, you've just taught them how to treat you.
Don't put up with bullshit! Be a powerful being with a gentle heart.