The best is when laowais try doing this back to the Chinese.
Go ahead, and try it on your neighbors:

When you see your neighbor coming back from the store, say this: Mai le dongxi ma?/买了东西吗? (Bought some stuff?)
Guaranteed they will look at you like you're crazy. Why is this laowai asking me if I just bought something?

My point is, we can't understand it. And we [unfortunately] can't participate! haha