3. Orange Line
Yes, it can be dirty and cramped and loud. And yes, its on-time record is abysmal. But here's something else to think about: as we write this, an Orange Line train caught fire 24 hours ago. Also, a passenger was arrested a couple of weeks ago for a "lewd act" towards another passenger. Also also, there was that famous blow job seen ‘round the world (or at least in the New York media): a BJ performed on the State Street platform... at 2:30pm... that was photographed.
All that said, we think the Orange Line gets an unfair rap. It’s no more or less dangerous than any other system, and it meets up with every line in the city. So it’s like the MBTA connector.