The best of the Barcelona "supermarkets" (Midwestern Americans might think of these as quick…read moregrocery shops), not as quaint as the independently owned and operated groceries but cleaner, cooler (important in a heatwave), and better stocked. I love that decent local wine is cheaper than Coca Cola, there's a wide selection of chilled rinks (important in a heatwave), and here's the place to stock up on bottled water if you're trying to see all of Barcelona in only 10 days. Very nice selection of what I would consider to be high end chocolates, snacks, cheese and other dairy, and fresh produce but by Barcelona standards are just typical snacks, chocolates, cheese and other dairy, and fresh produce. You can get small amounts of laundry soap cakes, excellent for travelers (travellers if you're English), and the staff is competent, friendly (not in that fake "have an nice rest of your day" American way), and polyglots. For some odd reason, Catalonians can understand my bad French better than French speakers. Don't forget to bring a grocery bag.