Picked up the car at Barcelona T1. Waited in line for about 15 minutes. The customer service representative was very friendly and although they did try to sell additional insurance, they weren't pushy. Just say no if you don't need it. The car pickup was in the underground garage, simply take the keys and go. Returns are at the same location as the pick-up. The parking lot is next to Area A. Make sure not to park in the wrong lot, or you will have to pay. Although there was only one person checking the returned cars, the process was quite fast, taking roughly 10 minutes per car.