In reply to Bob Kemp:
Good article, I think they are unjustly vilified, and have always been fascinated by them. Yes, yellow jackets have a painful sting and are best avoided. The worst thing you can do is to started flapping and waving your arms around if they start buzzing around you because that just agitates them and increases your chances of being stung, or worse still you might knock it with your arm into someone else, who then gets stung because you pissed it off. Best to stay calm and it will either loose interest or settle on your strawberry jam cream tea.
Even if one actually lands on your bare skin it generally won't sting, just let it walk along, and it will loose interest and fly off. If you are unlucky enough to get stung, it's generally the one you don't see that stings you, like one crawling in your bathing towel or up the curtains you have grabbed to close!
Remedies for stings include cutting an onion in half and putting it on the sting as soon as possible afterwards, various ointments including "After Sting" which I keep in my first aid kit (smells like pee as it's ammonia) and antihistamine tablets which I carry for hay fever.