In the very touristic Graça area, there is this heaven place, hidden from tourists. This café belongs to the theater da Garagem. It has an amazing view, the atmosphere is peaceful and with a lot of light. They don't have wifi if you plan to work there though..
Off-the-beaten-path, just outside Lisbon. The best seafood! Humble and local atmosphere.
Check the opening times first + Sr. Domingos doesn't open when his football team plays!