I would argue that we do not all experience anxiety the "day after" for many reasons. First, we do not "misinterpret" potentially anxiety producing physiological phenomenon. Anyone who has had a hangover could tell you that dizziness, racing heart, perspiring, difficulty concentrating, sleep disturbance, muscle tension etc, are all par for the course. Obviously, these are all common anxiety symptoms as well. Is it not possible that these collective physiological experiences could lead an individual to panic? Further, a hangover paired with panic on several occasions can lead to generalization of anxiety, clear cut conditioning, where drinking becomes the conditioned stimulus and anxiety the conditioned response.