Why are hornets so darn mean?

I haven't seen any untill today. Went out to hang something on the line and for no reason the nasty thing bit or stung me. I only had it happen once before and today was easier to understand. Feels like a burn. I remember years ago I was on a dirt bike and one got into my collar bit me a bunch of times before I was able to stop and understand it was a bite not oil splashing on me. Well I got it off and dressed carefully went out there and watched to see where it came from, a decoration sideways and the things made a nest inside. So at dusk when they all go home to the nest I took a bucket of dirty dish water and filled the thing the nest was floating. No more mean wasps now