Adda is a neat little coffee and tea shop with a good selection of teas, as well as creative speciality drinks and snacks. I tried a merlot caramel cappuccino ($3.45, 8 oz) which was just the thing to warm up with after a walk. Adda is probably a little pricier for Pittsburgh, but not as expensive as similar shops I've seen in Portland with $6-7 lattes - plus the baristas here today were very friendly and helpful. It might not be the best place for working since there aren't too many tables, but it's worth stopping by to grab drink to go.