Why aliens don’t contacted human 

They're Watching... and Laughing: Why Contacting Us Would Be a Reality Show Disaster

Forget Roswell and crop circles, the real reason aliens haven't contacted us is far more embarrassing: we're the galactic reality show they can't tear their eyes away from. From political squabbles that would make a Kardashian cry to international incidents sparked by misplaced IKEA furniture, humanity's daily dose of absurdity provides endless entertainment for our extraterrestrial observers.