I had occasion to ask someone for a favor recently. I will not indicate the relationship of this person to me, nor relay the nature of the request as in my view these things are irrelevant, or should be. The person said no and then proceeded to give a litany of reasons why they could not do this particular favor for me. While I could appreciate the impulse to try and soften the blow, or make me understand their position, or whatever I began to wonder why this person felt so compelled to provide such an exhaustive list.
When I ask a person for a favor, implicit in the ask is the understanding that saying no is always an option, and should that be the answer there will be zero negative ramifications, irrespective of the reason(s) for saying no. Do not ask for or expect an explanation when asking another for a favor. If you do you are not asking for a favor, but rather playing an elaborate extortion game.