This happens quite often in New York. It’s not very clear which train goes in which direction. It takes some getting used to. Even with the assistance of Google, signs, and asking the locals, it’s possible you still made the mistake of getting on the wrong train.
Mistakes like this happen all the time.
The greater mistake, though—the one that will cost you—is staying on that train.
Yes, you’ve already spent a significant amount of energy to get on the train. You were sure you made the right choice. But you found out you didn’t. You’re on the wrong train, and continuing in the wrong direction won’t magically make it right.
If you really want to go in the right direction, you’re going to have to first get off the wrong train.