There is no more cruel act in a social environment be it among dogs, wolfs, monkeys, or humans – than abandoning. It triggers fear of death and is the grandest primal fear there is. To be abandoned means to be left to die. If your pack, or your mother abandons you, it means you are a worthless piece of shit. There were others more important and you were hit. You were not good enough.
This inflicts enormous pain. This is going to stay with you forever.