Good mistakes

As I drove along, the mailbox numbers jumped a bit.  I was close and even though the mailbox wasn't numbered, the house had work vehicles in the driveway.  I pulled in and parked. 
When  I entered the open front door, the woman asked if I was the a/c repairman.  
"No", I replied, "I'm looking for #64".
"That's the next house" she said.
Of course I had to ask, "Before I go, what's wrong with the a/c.?"..........
30 minutes later, with the a/c working, I left and went next door to like I was supposed to.
Of course, I had to explain why I was late.

They'd been waiting for days to get it fixed, and a fortunate mistake on my part resulted in it being handled.

When 'No' is the right answer to give a customer

We recently had a customer who wanted an attic/roof fan to help keep her top floor cooler (they work great!).
But her house would not have benefited from the fan due to house's layout.  So, we suggested instead to have a good Vornado-brand fan, and a window air conditioner.
She really wanted an attic/roof fan and asked about different ways to do it.  And we felt bad saying 'no' because we knew she was disappointed.
Hopefully, after she has her fan and a/c unit, she'll appreciate that she's saved money and got what she really needed.