Pointing at Drivers?

[Grog]

So far the drivers I'm dealing with have been really courteous, but I did get very nervous when, as I was puffing up a hill, an oncoming car full of teenage boys slowed, a window rolled down, and a kid shouted at me -

"You can do it!"

I am quite sure many drivers actually do that sort of things to be nice... but when it (or similar) happens to me, I always feel like replying:

"Can you?"

And I HATE it when some honk as a way of expressing their support/cheering.