I'm happy that a friend at work just got laid off
Why would you be so happy about someone being fired at work?
Because she was always so damn loud at work, yet never opened her mouth to tell me anything important.  She only ever talked about gossip, and I'm tired of her.
As much as she annoyed you, it's rude to celebrate what must be a tragedy for someone else.  It also sounds like this woman wasn't your friend at all.  If someone else annoys you at work, just let them know that you want to concentrate in peace.
Cry me a river.
It is wrong to take pleasure in someone's failure. It is rude to celebrate tragedy and to claim someone as a friend if you secretly want them to fail. You should be more kind and considerate to others.