I get 400+ emails and 50 phone calls every day. Mostly candidates looking for career opportunities. I respond to every single email and phone call personally. You may think that is silly, however I feel it’s the right thing to do.
People that don’t call or email me back are a real hot button for me. It’s disrespectful. It says, "you are not important to me." My philosophy is that you should never be so self-absorbed or self-serving that you stop caring about others. If someone calls you, call them back. If they are "asking" and you can’t help, a simple no thank you will work. If you are invited to an event and commit – show up.
There is one exception to my "call everyone back" rule. Once I say "no thank you", if you call me again, I won’t return the call. I’m not in a position to say "no" two or three times. Although you may not value my time, I do.
The one thing I do keep in mind is that there may be a legitimate reason for someone to not return my call. At the top of that list are health issues and family emergencies. When someone has a personal crisis, everything else is off the radar. So before you go off the deep end, make sure there was not a legitimate reason for the lack of a return call.
A close companion to "not calling back" is "not showing up." I recently hosted a CIO event where only 20 of the 35 confirmed attendees showed up. Five of the "no shows" were unemployed. Later the same people that flaked out on the event called to ask if I could represent them and find them a new CIO job. I called them back right away with the answer – no thank you. The Godfather says you can finish ahead of 90% of the masses if you just show up!