Travel is fun when you've got a destination, have no idea how to get there, but know that you're going to get there anyway.
It's equally fun when you've got a map, and simply decide to wander.
It's less fun when you've got both a destination and a map, because then you've got an artificial experience. And by definition, such an experience takes away (or severely diminishes) the best feature of good travel - Serendipity.