How do you come up with a good idea for your business?

Most people believe that the thing stopping them from starting their own business is a "good idea". I hear people say things like: "I just need an idea". "All the good ideas are taken" or "I had an idea for something but then somebody else did it". Most people put ideas on a pedestal and scour the earth for the right one but they're making a huge mistake.  If you search for ideas you will never find one. You must go looking for problems instead.