Steve Kamb told me that the best and most polite excuse is just to say you have a rule. “I have a rule that I don’t decide on the phone.” “I have a rule that I don’t accept gifts.” “I have a rule that I don’t speak for free anymore.” “I have a rule that I am home for bath time with the kids every night.” People respect rules, and they accept that it’s not you rejecting the [offer, request, demand, opportunity] but that the rule allows you no choice.
- Ryan Holiday