Fiji has over 300 islands- I have seen about 25 so far this trip. I'm concerned that "the wow factor" no longer applies. Yet if I take an imaginary a ride down Southern California's Carmageddon- Interstate 405, breath in some smog while stuck in bumper-to-bumper traffic. I still want to escape to MY reality--being in the South Pacific! I love the Free Parking for all boats, ships and anything that floats.
The Law of Diminishing Returns is the theory that the more your experience something, the less effective it becomes. Think of the drug addict that needs more and more drugs, just to achieve the same high.
Beyond that point, more and more gains in any one particular area adds less and less to happiness. So in a sense, you can have too much of a good thing. The more you experience of the good thing, your overall happiness will decline.
I am needing a larger and larger DOSES of paradise-Bora Bora, Moorea, now Fiji---to get the same feeling I had when I simply visited Europe or even Canada. It's STILL working!