-Aliens do exist but most are either humanoid (85%) or are shape-shifters that can change into humans (5%), the rest are non-humanoid, non shape-shifters. The humanoid and shape-shifting variety are walking on the Earth today and your friend, girlfriend, or neighbor could be one. If they are living among us most likely they are harmless, it's the ones that refuse or hate to live among us that are dangerous.
-For milk, beef, renewable natural gas (methane), religious reasons, and for comic relief when twisters suck them up.