PayPal is run by imbeciles. I was once scammed on eBay by a buyer who received my item, then returned a broken identical one, notifying PayPal that I scammed him. Without even looking at my sales record or waiting for my response, they took the money out of my account and closed the issue.
After a month and a half of fighting on the phone with people who can't comprehend basic logic, getting an affidavit notarized, AND submitting photo evidence of the switch: I was only awarded 80% of the original amount.
The buyer was allowed to continue using eBay and PayPal to scam people, and I got negative feedback.
From this experience and the countless others posted to blogs every day, it's astonishing people still use the service.
Boycott PayPal!