Although he didn’t get the promotion he had been expecting, he put on a good face and congratulated the people who did.
If you go to attire yourself, you're covering up who you are and trying to be someone else. You are trying to feign. You are trying to wear a lie. You are trying to pretend.
While you go to feign that you're someone or something else, someone calls you out on it: "you so (よそお) much a liar!"