These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
One episode literally so, as a guest wants to experience a recurring nightmare all the way through to the end which she previously always missed when scared awake.
The Untwist: After the third or fourth time it was used (which is to say, early in the first season), the discovery that a fantasy love interest was actually another customer with a similar fantasy (who had presumably arrived on the island via a different means from da plane) grew to be expected.
Another Untwist: In sports fantasies, a guest will be given a magical piece of sporting equipment - a magic riding crop, magic ice skates, etc. - but is told at the end after he won the Big Game/Big Race that the items were ordinary and 'all the talent was in you when you started to believe in yourself'.