Humans will always endure suffering - even accepting the fact that we're going to die will cause us suffering, and from that stems a little pessimism and negativity that all of us are susceptible to.
Last weekend a young man asked me how I remain so positive. “It seems all the negativity in the world doesn’t affect you,” he said. I had no more than a minute with the young man so I offered this: It’s all about where you choose to put your attention, and I choose to be happy.