Cafes have become one of my favorite experiences here in Paris. You can run into many cafes on every block, each with its own unique atmosphere. Sure, it's just a food and drink establishment, but I've found that cafes really capture what I love about the French lifestyle.
My favorite so far is Cafe Blanc, just outside of my studio. I usually walk in, say hi to the staff, and sit down wherever I'd like. I always bring some homework to do. Sometimes I can order just a coffee and stay for hours reading, and never feel rushed to leave to make room for other customers. I don't think I've ever been asked if I want the check - it's usually just slipped onto the table or I can ask for it whenever I'm ready. Aside from having my water refilled, I'm left to myself to enjoy my book, talk to whomever I'm with, or watch what's going on outside. All the cafes have huge windows and outdoor seating. Even on the coldest of days you'll see people sitting outside enjoying a meal, and many cafes have outdoor heaters as well.
Cafes are all about the relaxed feel, good food, company, and conversation, and just a pause from everything else that's going on!