Com-passion means to "feel with". And John Gottman notes that when people make amends and get closure after an "uncomfortable" time/argument, the memory of that pain actually diminishes. But if things are not resolved, we hash over things over and over. This is know as the Zeigamik Effect. The superficial "just let go" philosophy doesn't work! That is repressive and doesn't deal with the pain of what happened and no responsibility, healing nor problem solving occurs.
We have so little tolerance for uncomfortable feelings.
I'm not even talking about unpleasant outer circumstances,
but that feeling in your stomach of I don't want this to be happening.
You try to escape it in some way,
but if somehow you could stay present
and touch the rawness of the experience,
you can really learn something.
-Pema Chodron, Buddhist nun
This spider illustrates how some deal with conflict - devour the other - or silence the other. At least the spider is doing good by killing this fly. Spiders kill about 2000 "pests" in their lives! What a great natural "pesticide"!