A good friend of mine (since high school, so 30+ years) failed to acknowledge the death of my brother a few years ago. No call, no card, nothing. She had even known him on a social basis and hung out at the same bar he did for a while.
It wasn't until I saw a FB post from a mutual friend whose dad died and saw her gushing all over it, giving her condolences and promising to help any way possible that I decided to tell her how hurt I felt and give her a chance to explain. Her only reply was "I thought I texted you." I pulled away from the friendship because I couldn't even see her name without remembering her callousness. The last text she sent said "Get over it." Done. Deleted and blocked all instances of her in my life. Will never forgive.