Normal
It is a good rule-of-thumb to be back on the ship at least 45 minutes to an hour before sailing time. This might not be "fun" for you but there are, on average, 2000 other people on the ship who took whatever precautions necessary to make sure they were back on board in time and, believe it or not, they could not care less whether or not you are back on the ship after a port call. This is why the captain, cruise director, daily program, cruise ticket, ship staff, ship announcers, literature in your room and other passangers are constantly telling us to be back on the ship well before sailing time and that time is posted and announced very clearly and exactly all day, every day throughout the cruise. You are either illiterate or exceedingly self-centered. Welcome to cruising and, no, 2000+ poeple did not pay good money for a vacation so they could have the honor of waiting for you. That is why, DUH, the ship leaves regardless of who got back on unless you were booked with a cruise line excursion.