Don't take the A-Train to Washington Heights after the 1, 2, and 3 trains have been stopped running uptown. It will feel like the whole population of New York City is at the 42nd and 8th ave station.
When I grabbed the 2 train at Times Square, I was ready to kick back with my novel A Summer in Europe (literally a Nancy Meyers rom-com in a book), and when we stopped right before we reached the 50th street station, I didn't think anything of it. The train was stopped in the tunnel for an hour. That means I was standing in my adorable, painful wedges for an hour. Even though the last couple of chapters of A Summer in Europe were riveting, I couldn't help but wonder when we were going to get out of this mess. The conductor came over the speakers a couple times, but never gave us any real information.
Finally, they said they were turning the train around to go back to Times Square, and there were no longer any 1, 2, or 3 trains running uptown. They directed us to take the A or C train uptown. After walking a block over, the A and C train station was PACKED. It didn't help that some old guido dude was trying to rub up against my backside. We waited 10 minutes, and when the A train finally did come, it was PACKED. No one could get on it. I knew I wouldn't want to be on a train that full with this weirdo pressing up on me.
Two minutes later, I found myself up on the street, trying to remember every movie set in New York City that I've seen, and how the characters flagged down a cab. Was there a technique? Did they pull over for someone who had one finger extended or all five fingers waving? If there is a technique, I clearly don't know it. While many of the cabs were full, I was unable to hail any of the empty ones. I walked around the north end o f Times Square for half an hour while I hunted one down, and finally found one stopped at a stoplight.