I think it's good to be positive. But in order to effectively do positive things that make a difference, we have to stay informed of the bad things that are happening.
I have friends who have told me "Oh I don't even watch the news or keep up with the world anymore because it's always bad news and it just depresses me."
Well I believe if too many people do that, it just allows greedy cruel rotten people to do whatever they like because no one puts up a fuss about it. I don't believe the world will get better by merely thinking good thoughts. I think people need to get depressed and they need to get angry enough to challenge what's been going on in the world. People have become too passive and complacent, sitting home watching mindless tv shows, thinking no further than their living room couch.....and we now see the result. All indications are that things will get way worse before they get better.

So my view is to YES spread positiveness and love....not only by committing acts of kindness, but by staying informed and by making/demanding changes for the better, changes both large and small, global and local. By getting fed up and by challenging the wrongs in our world we change our world. Make things more positive by taking positive action.