Yellow Jackets - I'm sure they have a purpose besides stinging people, right?

I don't remember having been stung by a yellow jacket before, but I had that awful privilege yesterday as I was using a hoe to dig out the roots of some pesky weeds. I think I was stung 2 or 3 times on my right foot. I did get the opportunity to flip one of them pretty hard and then took off running into the house. I immediately applied ice to my foot and took some benadryl. I figured it would sting for a while and then start to go away. Instead the pain became more and more intense and felt like my foot was in a vice that kept getting tighter and tighter. I have always had a pretty high pain tolerance, but I tell you, this was one of the most painful things I have ever experienced. Artie finally convinced me to go to the emergency room and I was given a steroid shot and something for pain. I'm better today but my foot is still a bit painful. Today I just wanted to say that I'm very thankful for drugs and to know that I'm allergic to yellow jackets. I'll do my best to avoid them in the future.