I just recently re-discovered the mind warping Wait But Why website thanks to the Back To Work podcast. If you want to feel really small and change the way you look at the night sky then read the article The Fermi Paradox.
Continuing to speculate, if 1% of intelligent life survives long enough to become a potentially galaxy-colonizing Type III Civilization, our calculations above suggest that there should be at least 1,000 Type III Civilizations in our galaxy alone—and given the power of such a civilization, their presence would likely be pretty noticeable. And yet, we see nothing, hear nothing, and we’re visited by no one.
They rest of the article continues to speculate as to why.