Lie to Get Ahead

Your post suggests that honesty is not only not the best policy, but will lead to personal failure, and should not be used. I agree with you that messages/information need to be delivered tactfully and with thought. But I disagree that the solution is to offer a lie.

Why isn't the obvious solution to offer honest, meaningful "message-level" answers instead of blunt, uninformative answers?

With your example, the spouse can answer that 80's leggings make anyone look terrible, that he loves her, and will plan to continue loving her, that he finds her attractive in ways that were not present when they were both younger. In business, you can answer "No our product doesn't do H, but it does J." You can answer "No I can't be sure that the lights will stay lit in the morning, but I believe that it will, because of X Y and Z." If your customer walks, and your business fails, then so be it. Your business did not fail because you spoke the truth, it failed because you couldn't keep the lights lit. There are many ways to appeal to people without resorting to lying.

I would encourage you to "conquer fear and embrace possibility": being honest is hard, it will cost you, but it is the only way for human beings to become "authentic and complete".