OK, picture this:
You're on a fast Club ride, and for the first time ever, you're able to hang with the Big Dogs through the hardest hammer section. After all the other 'weaker' riders have been dropped, you're still there. OK, you're hanging on for dear life (with your tongue dragging on the road), but you're still there.
Here's the feeling I'm asking about:
When the Top Dog rotates to the back of the line and sees that you're still there, he (or she) has that look of impressed surprise on his face.
Because normally you're long gone by this time.