Most anyone can be a model crew on a good day in paradise. How you are the rest of the time is what makes you stand out as sturdy crew. Our powerboats zip around effortlessly, often making trips in short order which would take hours longer even by car. Any trip to shore, even when it seems right over there will probably be about two hours out of the way of a sailboat on its course. Incidentally, most skippers encourage crew to bring a cell phone if you have one.
Time moves in a very different way on a boat.
Be prompt and ready to cast off when you arrive. Don't keep everyone else waiting for you. And at the end of a sailing trip, unless other plans have been discussed, expect to help clean and close up. This usually adds another hour after you've arrived back at port. You can cut this short by starting to clean up below long before you're back, while your skipper is bringing you in.