Life can be somewhat challenging. Nature itself provides earthquakes, volcanoes, floods, sharks, scorpions, deer ticks, and lethal bacteria, but mainly these can be avoided or accepted. The more interesting point is that even when things are relatively good and peaceful for stretches, someone will almost always come along to instigate war and bloodshed, by seeking control over resources or to rule the minds and lives of others. Mankind cannot live without pain, it seems; when pain is not provided by nature, people will the provide their own, like air rushing into a vacuum.
Perhaps just being alive in a simple way, growing old and dying gracefully in the cycle of life, is too much for the human soul to endure. Or is it "not enough"? Are we "always seeking more" when what is, is enough?
Bonus: Ask yourself this question: What is gravity? Yes, we know what it does, but what IS it? Also, why do bigger bodies (or "masses") have more of it?
Another one (a friend asked me this one last night): If we all originated as little black Bushmen in Africa, how is it that some who went East to colder climes became sort of squat and squinty-eyed with dark hair and eyes, such as Tibetans or American Indians, and others who went West to colder climes became tall and blonde with blue eyes, such as Germans, Dutch, and Scandinavians? (He believes that these Scandinavians were seeded by extraterrestrials, but we won't go there.)