I think that if we get over our economic, social and environmental issues, many of us will have a good chance to see the next hundred years or more. Technology keeps advancing on many fronts and there have been a lot of advancements in our understanding of the causes of aging.
I think we will have to become "nice people" as a global community if we have any chance of continued survival. Any advanced civilization that goes beyond our present technology will probably need to become "nice people" too. Thus I'm not particularly worried about any encounter with them.
Yes I see your point. Either we become nice or we self destruct I suppose. I hope mankind can do. I am not sure if we can though.