How much credit should be doled out for various accomplishments?

I won a Grammy Award for singing in the chorus on the best orchestral performance released in 2009 (incidentally nominated in two other categories). So how much credit should I get? Probably not much in the grand scheme.

How much credit does the water-boy for the Superbowl-winning team take? What about the receptionist at the Obama campaign headquarters? Or the guy who cleans the trailers on-set for the Oscar best-picture?

What about being the 2nd employee at a wildly successful company? How about the 500th employee at that company?

Do you tend to give too much credit or too little credit in cases like these?