I wish I knew Zack. It's an interesting phenomenon. Maybe because everyone's emotions are so raw? I dunno. In my experience, the situation always sucks.
Do you mean about the person who died or in general?
Death often helps us put things in perspective because we realize its finality. We may have guilt or other emotions to cope with about the person, so we may feel more empathetic or have regrets. And, like JaneS said, we can see the good as well. Our perspective changes. Compared with the finality of death, any wrongs that were done often fade into the background. They no longer matter.
As far as "show their true colors" goes... again, you'd have to be more specific. There are people in my life who I keep the peace with only out of respect for someone I care about. I'm betting everyone has someone that way. Plus, as we cope with own guilt and other emotions, we may lash out at others. Or, maybe we feel like someone is disrespecting the one who passed. I can think of my grandfather's funeral, and all these came into play. My grandfather was the glue of the family. Without him, the siblings wanted nothing to do with each other. That was true in life, but when he needed them together on something, they'd join up out of respect for him. After his passing, it was every man for himself. One sibling was pissed because another wasn't there enough and she felt alone. Another wanted to include a military ceremony in the funeral, while another said it wasn't what he would have wanted. That almost came to blows. We all have these bubbling storms of emotion all the time, but the emotion that shows is different. We're ok showing anger and hostility, but it could be shame, grief, regret, and a million other things. It's not fair to call that someone's "true colors." It's grief. Processing it takes time and we each have to do it in our own way.
Also, memories, by their very nature, are selective all the time. It's part of being human.
WM BARR . =ABSOLUTE TRASH 