A client hired me to redesign their business cards after they got a new corporate identity. I asked them to email me their logo in .ai or .eps format. They sent me a low res .jpg with a watermark symbol on it.

I did a mock up of a card using the low res logo as a place holder, and let them know that once I received their vector logo, I could just insert it into the design.

Client: Yeah, you’re just going to have to go ahead and use what we supplied.

Me: Are you sure you don’t have an .ai or .eps file of the logo kicking around?

Client: Our old designer won’t release the vector files until we pay them, so we’re just not going to pay.

I fired the client. Two months later, I saw the owner at a networking function. He handed me his card, which was my design. They had the cards printed from the proof I originally sent. Which included the low resolution jpg logo that had a giant watermark over it.