Ooh, boy...can I sympathize with the OP.
I'm reminded of a quote from the first MiB, when J asks K why they don't just tell everyone about the existence of alien life, because people can handle it. K replies, "A person is smart; people are dumb and panicky, and you know it..."
My own feelings about humanity have always been deeply conflicted. One of my favorite (!) studies is military history--strange for an avowed pacifist--and military history, unfortunately, is full of massacres, pointless battles, and idiotic mistakes that sometimes cost the lives of millions. The news today gives little encouragement: for every scientific advance there's news of another repression, for every act of charity another act of greed or stupidity (just look at Wall Street), for every problem recognized there is another ignored.
So, at least once a day I think the human race is a dead end, and hope fervently that some comet will come along and destroy the whole mess so nature can start over, hopefully with another intelligent species that can get things done instead of thinking of new and better ways to smash each other over the head with clubs.
But hey...childhood is like that. I know; I've done my share of prickish acts growing up, acts I now regret, but I learned and will not repeat them. The optimist in me tells me that's where humanity is now, in childhood--learning its limits, getting burned now and then, but coming through a little better year by year. Yes, it's easy to despair of humanity's present, but in the Western world alone, look at how much things have improved: we don't have the rack. We don't burn people at the stake. We don't have trial by ordeal, or legal blood feuds. We don't build up capital with the Middle Passage. Our democracies are imperfect, but are still a step above autocracy and the divine right of kings. Literacy has improved, justice has improved, health has improved--I must believe people are perfectible.
People are surprising; there are individuals I thought were friendly who most definitely were not, and others I thought would be contemptible or simply "not my type" who were wonderful. Every day my preconceptions are challenged. For instance, I recently visited a friend in southern Alabama. One day I'm walking along a rural road near his place, when a pickup truck stops beside me. Here goes, I was thinking, hick sees a black guy walking along the road in Lily White Land, stops and hisses at me that "We don't care much for your kind round these parts," and I'll thereby join the ranks of the millions of blacks who've been insulted by Dixie".... So he leans out the window, and asks "Care for a lift?" I saw not a drop of real suspicion, disdain, or veiled malice in his eyes, and I must admit that it was one of the most quietly shameful moments of my life. Yes, James Byrd-dragging mouth-breathers exist, but painting millions--let alone billions--of people with the same brush without giving them the benefit of the doubt is moronic, and that's exactly what I felt like at that moment.
The point of that rant is this: that though I personally remain a cynic, I simply cannot help but believe Hemingway's "The world's a fine place, and worth fighting for."