Last week I bought an OEM copy of Windows 8. Turned out the product key included was invalid. I called Microsoft gave the lady my name, email and faulty key. She confirmed it didn't work and just like that gave me a new product key. She didn't ask for proof of purchase or anything. I was utterly speechless. I couldn't believe that of all people Microsoft would have such great support. They solved a problem I was fully expecting to take two weeks (shipping back and forth) in under 10 minutes.
This reminded me of an issue I had with a Logitech G500 mouse a year ago. The left mouse button stopped working so I contacted support. The guy didn't ask for any proof of purchase and sent me a new mouse just like that. I was even more surprised to have it arrive the next day, turns out they had used overnight shipping.
Has anyone else had a customer service experience they thought was going to be painful but turned out better then they could have ever imagined?