That is a very good post.
Indeed, people don't want to talk about what people did good, they prefer to talk about the negative things.
Its like in a joke.

An old man sitting alone on a bench with an angry face, then a young guy sit next to him and ask him what his wrong.
The old man said, do you see that bridge there?
The young man said, yes why.
Well said the old man, i helped build that bridge.
And the man continues, do you see that building there?
The young man said in a curious way yes.
Well said the old man, i helped build that building.
And he when further, and said, do you see that tower there.
The young man said again, yes of course.
Well i helped with the tower to, and do you really think that people will call me the guy who build a bridge, tower and building?
The young man said, yes of course you worked on those building.
Well it was, until i f....d a sheep.
Since then, i am the old guy who f...d a sheep.

Ok the joke is extreme but , moral of the story is, people can forget the great things when someone goes over the line or make a mistake, or not doing what others aspect from them.
While the truth is, nobody can be perfect for someone else, we all can learn from our mistakes and move on and improve yourself. To ignore the good parts of someone, while they made a mistake or did something wrong is stupid.