Is it good to hold in the big portion of anger that's been rotting inside and growing?

Well is it? I always had issues with this, and today…has been one of those days where I had the mind to make a bloody mess on a desk or anywhere I can break their mind…Literally… I guess I can say I’ve been very angry lately and I’ve been keeping it stored in this…..er…behind fake smiles and false feelings and happiness.Is this something good to do or not? It’s been this giant fire ever since I was a little kid, and it’s always added on since then. I’ve never had a chance to actually let it out… Fully…Just little portions, but by then it grows two times then what I had before…I’m such an angry person but I never want to show it. My mom always tells me to release that anger when the time is right. I just want to know if this is a good thing or not. Is it?