A word for something you didn’t know you’d like
I thought delight might be it, but the various dictionaries I checked make no mention of the sense of surprise or unexpectedness, defining delight as simply heightened or extreme pleasure.
To clarify, I'm referring to the pleasure arising from some unexpected thing, not encountering pleasure contrary to expectations.
For example: you book into a cheap hotel and have low expectations for a good experience (dirty linen, no room service, noise, etc) ... but then you discover that your favorite band is doing a gig there.
Or: you book into an expensive hotel, and figure there will be the usual roll call of luxuries perfectly executed to make your stay a pleasure ... but then you discover that your favorite band is doing a gig there.