5. The idiot who feeds the raccoons/seagulls/pigeons - This misplaced act of altruism guarantees that everyone at your picnic will be unnecessarily exposed to possible rabies/mange/bird poop on the head.

4. The lady who won't pick up after her dog - Nothing says "I feel ready for a pile of barbequed ribs" like spending 15 minutes cleaning off the bottom of your flip-flop using a stick and a Publix receipt.

3. Sports show-offs - These brahs have a genetically programmed compulsion to violently throw the football back and forth no less than 5 feet from your grandmother's face as she attempts to take a bite of her "Happy 100" cake at the family picnic.   

2. The man - Cops with their open-intox tickets, park rangers and their "Please keep the flames on the grill below the tree line sir," the ER nurse and her "You shouldn't have consumed coleslaw that sat in the back of your PT Cruiser all morning"...authority figures are natural party poopers - they can't help themselves.

1. The guy with the acoustic guitar - He passes by half a mile of empty sand only to set up shop 20 yards from your family's picnic on the beach. Close enough to hear all of the noodling and every tenderly--if feebly--strummed note, yet just out of potato chip-pelting range.