I find that people's outlook on humanity comes down to where they focus their attention. We're definitely a mixed bag of wonderful and terrible. But, the vast majority of people, the vast majority of time are boringly nice to everyone and everything. That boring niceness is as common, as important and as easy to forget as air.
Also, the world has many very bad aspects and some of them are getting worse. But, on average the world is getting to be a better place rapidly. Today is the most peaceful, most healthy, most just, most educated, most comfortable time ever. As people who were born and grew up knowing only such good times, we easily forget how so much of what we would consider atrocities today was common a mere few hundred years ago.
We have adjusted to be tremendously more sensitive than our ancestors. And, we are infinitely more informed about every bad thing everywhere in the world. That doesn't make everything OK. But, it is a great sign that more attention and effort is being focused on the remaining problems than ever before. If you are deciding to focus your attention on the problems we still have, then you are a sign of how the world is getting better.
With that attention, you can find problems that remain. With some historical perspective, you can figure out which ones you can best help reduce. With some effort, you can be part of making the remaining problems in the world even smaller.