I've sailed multiple 3-night cruises (as well as longer cruises) and enjoyed them all. It's three nights, not one. It isn't "you unpack then turn around and it's time to pack up again", as some people claim. That's an exaggeration. A 3-night cruise is a great way to find out if cruising is right for you and your family. When given the choice and all other things being equal, I'd select a 4-night over a 3-night, but I wouldn't spend $2,000 for one night. (I also think the Wish is overpriced and she sounds overrated from what I've read about her, but that's a different issue.)
One tip I have for a short cruise is to unpack completely and stow the suitcases under the bed for the whole cruise. Don't be tempted to live out of your suitcase because it's a short cruise. Fully unpacking allows you make your stateroom a home away from home and enjoy the cruise experience more.
Another tip is to make sure your bathing suits are packed in your carry-on bag, so that you'll be able to enjoy swimming and/or hot tubs during embarkation day before luggage is delivered to your stateroom (which can take until early evening). Swimming or doing other fun activities on embarkation day is a great way to recoup from the stress of travel, and it helps you to make the most of embarkation day, and not let it feel like an empty or throwaway day. You'll also feel less fear of missing out pressure on the second day, because you'll have already tried some things the ship has to offer.
Finally, let yourself really relax. You can't do it all on a 3-night, so don't try. Do what you feel like doing. Rest when you feel like resting. Let yourself sleep in if you feel like it. Veg out, order in room service and watch movies or cartoons for awhile on the stateroom TV if you feel like it. Don't order your cruise around a checklist of must-dos. Reframe those in your mind as can-dos, instead.
Happy sailing.
