Have you ever walked along a street come across a ladder leaning against a wall or seen something foul steaming dead center of you passage to Chapters? Then have you gone out of your way to avoid these disturbances in the force?
I believe it is this principal that keeps us from making first contact with alien civilizations. We are the cosmic ladder not to be walked under or the universal lump of shit along the Milky Way. In fact I have heard that alien Mothers tell horror stories to their children about, the earthling lurking in your basement, in the potting shed with the cracked window or in your closet mangling space kittens. Eat your cabbage Spock or the earthling will get you. Billions of alien children go to bed terrified by the Earthling under the bed.
Did you spot the cunningly veiled mistake? if you did contact me and let me know, the prize is my undying devotion.