Well, I promised you a horror story, so here goes:
Although I've met lots of really nice people in this business, I've met my share of shady characters along the way. The worst of the bunch being a seemingly nice old lady whose shop I wandered into one day ... at the very onset of my antiques "career." While I as looking around, she asked if I had thing to sell as well. Well, of course I did! So, being the gracious colleague, I invited her up to my place. She came over that very evening, and picked out the best pieces I had, and told me she could pay me in two installments: one check on the spot and one post-dated one. Well, of course. Why not?
You know that "gut feeling" you should always listen to? Well, I didn't. As soon as the items were packed up, and she gave me her checks, she seemed to be in a real hurry to get out of my house. At that moment, I had the urge to say "forget it ... I want cash." But, that wouldn't be too professional, now, would it? And, so, off she went with several bags filled with my best antiques.
Do I have to continue, or can you guess how this turned out? Well, of course, the first check bounced, and I had no doubt that the second one would too. I went to her shop, but she said she had already sold the items and was waiting for payment from her customers and would make good on her purchases as soon as she got paid. I didn't believe her at this point, but I had no choice but to wait. When these excuses continued for over 2 weeks, I threatened to go to the police. Only then did she pay up.
I learned two valuable lessons from this experience: 1. Not everyone is honest, and 2. ALWAYS listen to your gut feelings.