I hate getting calls from people I sold stuff too.
Last year I sold a transmission for a 3000GT/Stealth to a guy about 1.5 - 2 hours from me. I had no idea of the condtion of the trans because I never got to drive the car it came out of. 2 weeks after I sold it to him my phone rings and its him.
My first thought was "aw SH!T."
I reluctantly answered the phone, and he reminded me who he was, and said "First off the trans is awesome. I can't beleive how smooth it shifts. Second, would you want to do a timing belt for me?"
Talk about a sigh of relief. Not only did I make $400 on a transmission, but I made $200 on a timing belt job. LOL