When I email or call you about a particular item and you say, "I have other interested people, but you can see it first before they do." Then don't tell me 3 hours later when I call to get directions to your house that someone else is already on his way to view the item and if he doesn't buy it then you'll call me back. That's tacky. And really, really annoying. Since I rearranged my day to fit your schedule of when you would be at home to show it.
That would be lovely. And help me not to fume for 2 hours afterward.