The Frank Stella’s are the best. They are all over the city and they always look amazing. Two of my favorites are the Saatchi and Saatchi lobby (pictured) and the Citi Corp building in Midtown.
For brunch, the classic dish to get is the Feijoada, but the benny is also solid (and i don't recommend a benny lightly)—you can also ask for ham and spinach together (my favorite). For dinner you can also get the same thing, or the Moqueca (shrimp stew) is incredible. Pro-tip: if you're there for breakfast on a weekday, ask for a egg and cheese (add bacon or ham or avocado) on a croissant. Not on the menu—sounds basic, tastes amazing.
Going for a stroll on Atlantic Beach is a fall Sunday must. I rarely go to the New York beaches in summer because of the crowds, but standing on an empty, windy beach is a total mind soother. Make sure to take a peek at the Miami-colored Catalina Beach Club. Beaches close mid-September.
The Future Perfect is my favorite place to shop for furniture / interiors, or pick up a small gift for a friend. They have a perfect mix of beautiful and strange objects, some of my favorites include the Animal Butt Magnets, Shrigley Salt & Petter Shakers, and the Bank in the form of a Pig.