You know, they say when a spirit spends too much time in the living world, they become corrupted and seek to bring others misery too. [which is an oversimplification of hollows, but ssssh.]

We miss people because they left an imprint on us. My children miss their mother everyday, and I miss her too. They'd want us to be happy, and not burden ourselves with their death. It corrupts us, rots us from the inside out until we can't remember who we used to be.