10 Hours of Walking in NYC as a Woman = 100+ people not leaving you the hell alone.
Oh, you might think, they're just being friendly*. But when some of those people were as creepy as the guy who walks alongside her for five minutes silently, then suddenly they all feel a lot more unpleasant to be around.
*If, for instance, you hadn't encountered this kind of thing before. I had a very sheltered childhood, so I wasn't aware of this until I was in my late twenties. I had my own issues with street safety, but they were quite different.