There are a few foods that you should avoid buying at Trader Joe's. One food to avoid is their pre-made salads. The reason for this is because they often times use old produce and the salad dressing can be very bland. Another food to avoid is their frozen pizzas. They are often not cooked properly and the dough can be very chewy. Lastly, avoid buying their cookies. They are often dry and have a weird aftertaste.