I was hit by a nest of the pests when I was 12 or so. I was stung 12-15 times. I became majorly allergic to the stings to the point that sting on my finger caused my arm to swell up to my elbow in high school. I couldn't close my hand at all.
My body has recovered over the years, my last stings didn't swell nearly as much, but I still hate those little things and when I find a nest on my property, it is dealt with using maximum force.