I am talking with a client and my phone beeps.
They leave a message and I call them back in a few minutes.
I get the reply form the person on the other end..."Oh, we already called someone else."
I know that we are in an instant gratification world, but if you really want an agent to work hard for you, you need to have a little patience.
Giving me a few minutes to call back is not only courtesy, but it may take me a few minutes to get the info you wanted.