I've always thought it was just a pretty word. xD It's in most of my usernames on various websites.
Not just because of Portal 2, either.
Serendipity, alluring, rapscallion, wicked, lunacy, shenanigans, darling, iridescent, and luminous.
I love the sound of these words on my tongue.
More words I wanted to add: whimsical, lovely, reverie, cascading.