Square Cafe is one of my favorite breakfast or lunch spots in Pittsburgh. Delicious coffee in their unique mugs ( I loved them so much I bought a couple for myself). Friendly staff and vibrant atmosphere. Must get the Brussel Sprout hash and if it's on special the Corned Beef hash. Also love their Chorizo Tostada and Salmon Crepes.It's also fun to sit outside and dog watch in the spring, summer, and fall. For Sundays if you can get there early before 9 (?) or very late in the day is best, though the early crowd generally equals quite a few screeching children (which is fine if that suits your needs - it's nice that it is so accommodating to families in the neighborhood). I like going closer to 1 on a Sunday (or just on weekdays) so I don't feel rushed to clear a table and can keep enjoying another mug of after breakfast coffee.