I find it amazing how much color and vibrance can be found In tropical islands! It makes landscape photography easy.
It must be the combination of dense blue skies, green palm trees, vibrant sands, tons of sun, and the multitude of colors found on swimsuits, and surfboards that makes Hawaiian photographs look so colorful.
I've read that healthy Auras if seen are vibrant colors which envelopes the person. With so many happy folks on vacation it maybe their auras that lights each photograph.