When most people come to visit Turkey, they have three things in mind... Istanbul, Cappadocia, and Pamukkale. It's almost like nothing else matters.
Something like visiting Machu Picchu in Peru, or Niagara Falls in Canada.
And normally, a popular tourist attraction is popular for a reason. There is something about each of the places mentioned above that makes it worth visiting. That is, if you can put up with the hoards of tourists and the inflated prices that go along with it.