Some people have a tendency to look at everything and see only the cons, the defects. This way they oversee the good things. Are you one of them. If so, do not be worry, this is not something permanent, this can be changed.
You, like all the people, were not born with that. You just learn that when you were observing the world and people around you. It is not yours or anyone else nature. It was impregnated in us by society.
Because of that, it can be changed, replaced. First of all, you just need to realise that you are doing this. Secondly, start to ask yourself. What I see good in this person, situation, item or whatever another thing? What positive impact it can have on me? How I can profit from that?
It might be a bit hard at the beginning but it is worth it. You start to feel better, happier, more relaxed. And I am sure you will agree with me, that this is what we, you, me and everyone on the planet want to really feel like.