It's a mixed bag, emotionally speaking, when you run into a subway station and see that of the two tracks that are running, both have idling trains with open doors. You hit the jackpot! No need to stand around cooking on a platform waiting for your ride, you get to hop right into a waiting train. But what's this? You have no idea which train is running which direction, and you don't know if they're running local or express. One wrong decision and you're stuck on the wrong side of town, backtracking before you even get to this point. The doors only stay open a few seconds; it's decision time. Some people stand on the platform and scream "downtown" or whatever outlying area they're trying to reach hoping that a kind soul (the only person on the train not wearing headphones) will give them advice and not lead them astray as a joke. I find the best solution is to stick your arm in the door and when you shout the question at someone, try to make eye contact with them. They're less likely to play a joke on a shouting person in that situation.