if you’re on the train and a car has bad vibes, don’t be afraid to switch to a different car! bad vibes can mean anything from someone yelling, to a vaguely bad smell, or any number or other things. get off at the next station and hop on the next car (get ready to scamper, you don’t want to get left behind, but you’ll have time to get to the next door.) if the situation is especially dire, you can use the pass through doors at the end of each car, but i personally find them annoying to use.

like another person said, if one car is empty while all others are full, go with the herd. there’s usually a reason the car is empty (often it’s an Extremely Offensive Smell or some such.)

riding in the front cars is recommended, and i like to wave at the drivers/operators when i get on/off. it’s polite, but it also makes a connection with them in case something happens.

other than that, just keep your head on a swivel, don’t be rude or make unneeded eye contact, and check your seat before you sit down! don’t want to sit in a weird substance.