To be honest, a train leaving early SUCKS. You show up on time, and you find out you missed it. Maybe the next one is in 40 minutes, maybe it's the next day.
(I realize 20 seconds early isn't that bad, but still, leaving early by any amount of time is a lot worse than leaving late)
(I realize 20 seconds early isn't that bad, but still, leaving early by any amount of time is a lot worse than leaving late)