Many of my 40-something friends rolled their eyes when I referred to cruising as "travel".... so I no longer do. It is a vacation.
Travel is wandering places like Costa Rica or Cuba for a month, meeting the locals, seeing the little sights, something which never appealed to me. I don't even do the shore excursions anymore, except if it's to a nice beach. Shore excursions are never long enough to do more than a cursory visit to a port of call, anyways.
Cruising has everything I could ever need, and then some, right on the ship. I just like being on the ocean.