1. Sometimes, you might be careless whilst locking your bike up. You might return in the evening to its parking spot, to find a tall, cute, male biker in a woollen vest asking whether the blue bike is yours, and to kindly unlock it from around the red one, which is his. You'll no doubt feel embarrassed and stupid, but he might be patient and kind, and very cute. He might work in the same building. You might dream of leaving notes, notes from the blue bike to the red, apologizing profusely. You might begin romancing vicariously through your bikes, in a charming film-esque game. After a time you'll no doubt ride away to the ocean together, and chat like old friends, red and blue bikes nestled in the sand.
2. It's very good exercise.