Here are two recent stories:

I was on the metro a couple weeks ago with my friend (she's Asian as well) and an old man who reeked of tobacco sat directly behind me and he proceeded to talk to himself in another language (it sounded like French but I'm not sure). We both felt uncomfortable sitting in front of him and the smell got unbearable so I tried signaling non-verbally to my friend to switch seats but she misunderstood me so when I stood up she moved to my seat -_- Anyway, when I stood, the man turned to us, looked us in the eyes, and said "Chinatown is THAT way! You missed it!" I'm sure he didn't mean it in a bad way because he had a friendly smile...However, it was awkward nonetheless.

Another incident was when I was waiting for my parents at the train station and a guy came up from behind me asking me to translate a cigarette box with Chinese writing on it. I don't even know how he knew I was Asian when he was behind me...