I really like Serendipity---for one thing, it's a high-class chocolate shop, and it's in the suburbs, no less! It helps to cement San Carlos's status, in my opinion, as the best suburb other than Palo Alto in the Bay Area, especially for food (eat that, Burlingame!)
Actually, given what Serendipity offers, you'd be hard-pressed to find something similar even in San Francisco itself.
So what's so good about the place?
-they have a good array of vegan chocolates (at least four or five different types), all of which are available for sampling, and all of which are delicious and unusual
-they offer vegan popsicles from San Francisco-based Pop Nation
-they have gourmet vegan hot chocolate, which can be made with either soy or almond milk; it's rich, thick and practically a meal unto itself
-they have a good selection of high-grade loose-leaf teas, in case you want something light to go with your sweets
In fact, I can't think of any other place in the Bay Area that offers vegan chocolates, high-grade tea and popsicles all in one setting.
My only gripe, and it's a major one, is that Serendipity has terrible hours. I mean, it's closed Sunday, Monday AND Tuesday, which is just excessive. And, of course, it seems like every time I want to stop by, it's on a Sunday, Monday or Tuesday.
Regardless, it's worth a visit and unlike any other chocolate shop/tea shop in the Bay Area.