You've got several options:
We recommend Philz Coffee -- it's a San Francisco tradition (and ask for their "Tesoro" coffee!)
There's a Philz Coffee in downtown San Mateo
This is the closest Starbucks, in the Bridgepointe Shopping Center
Just like with shopping, there are many, many restaurant options.
If you're looking for something fun:
Downtown San Mateo is a 7 minute drive away, and probably has 100 restaurants within a 10 minute walk. It's known for some of the best sushi on the Peninsula (like Sushi Sam's), with a wide range of options, including several great Ramen spots (Ramen Parlor is one of our favorites -- not fancy but authentic. Taishoken Ramen is also great, and more upscale. And there are many more options.)
If you're looking for a nice place to take your family, your team, or clients:
We think Pausa is one of the best spots in San Mateo. It's an authentic, upscale Italian restaurant, and they have a fantastic chef's table in the back. Stephen is one of the owners, tell him DROdio sent you.