I've actually been a magnet for old folks asking directions or the time. But part of me thinks it's because I look like a local even though I'm not.
When riding the subway, with all the weirdos that sometimes pop out of nowhere, I would rather have a quiet ride than have someone attempt to strike a conversation with me. And when I'm on a three-seater, I actually prefer that nobody sits beside me so I don't feel squished.
The only time I'd like someone to be friendly to me is in the office, when I'm settling my taxes, in the hospital, or when meeting people in a resto/bar. Everywhere else, I'd prefer them to leave me alone unless they need help asap.