This actually happened a few days ago at the service
station/convenience store where I work.
On the wall beside the office, there was a large sign bearing the
words "If we don't take care of the customer, someone else will." It
had been there for months, and no one really noticed it. But last
Sunday, the sign fell off the wall and landed on a customer's head.
I guess we took care of that one.
(From the "Rest" of RHF)