Alot of people have an innate comedic ability. Some people are just born with a good sense of humor the same way some people are born with inherently more strength or more intelligence. But just like you cannot become a body builder without training and you cannot become a doctor without studying you cannot become a comedian without understanding humor on a deeper level. Not everyone can be hilarious but anyone can be funnier then they are now by learning the rules of humor. And practicing them.