Yellow-jackets are wimps compared to the red paper wasp! Most aggressive wasps/hornets I've ever encountered.

i will have to respectfully disagree.
there is a little yellow-faced yellow paper wasp that is a mean little devil. but yellowjackets are still the worst.

If you disturb a yellow-jacket nest, they ARE coming after you, and they aren't going to give up! I've never seen any other hornet that will pursue an intruder as long and as far as yellow-jackets. However, you don't even have to disturb the red paper-wasps to get them coming after you in full force. Just walk near the nest. In addition, yellow-jackets sings really burn, but only for awhile. Whatever's in the red paper-wasps sting is mighty strong, as a sting on the arm or leg will cause it to swell up twice its normal size, and hurt for days.

Now from what I've been told NOTHING tops the sting of a European Hornet. I've talked to loggers who have been stung just once or twice and they were very physically ill--cold chill, nausea, diziness, etc.