Bacteria Infested

Everyday people make fuss about hygiene, which is not a bad thing. However we tend to be selective bout our hygienic tendencies. How many germs are on that tap after washing your hands or that cellphone you texting with while eating?
I  argue with my friends about finding hair in food. My theory is if eating hair was dangerous, the human race would have join the dinosaurs a long time ago. Not that i support hair in my food, but i just think people over-react when it comes to these things. Babies by nature put everything in their mouth, by then the body is already 
recognizing the germs and which ones it can handle. So we may find germs all around us, but how many actually harm us.
So surely there is food poisoning and all that but i think we are being driven to a state of paranoia. People kiss everyday, share cigarettes and drinks how many germs do we exchange then. we handle money while doing everything. How much bacteria is on a note? A extreme case is oral sex. expect for sexually transmitted diseases, I don not know of anyone who has ever got an upset tummy after performing oral sex. So what should we be afraid off and what should we not be afraid off?