Fun in the Florida Sun

I think it was because you went on a short 4 night cruise. Cruises with few nights cost less and tend to attract families, bachelor parties, etc. These people come to party, they will say hello to you but they have their social group established before they board the ship. Cruises with longer itineraries cost more which means they attract a demographic that has resources and this demographic generally attracts older people (not always but as a rule yes) and a longer cruise will also attract people who have more vacation time. A longer cruise like 9 nights or longer will have more solo travelers on board. The exception will be Norwegian Cruise Line which has the solo cabins and solo cruise group. The solo cabins are not on all Norwegian ships so do your homework and make sure you are on a ship that has solo cabins. (These cruises tend to be 7 nights). Norwegian has a staff member assigned to the solo group who coordinates the meet ups and makes sure the solos eat dinner together.