When you want to manipulate a situation in your favor (and you don't want to have to justify your feelings / say NO / or explain yourself), look at
To The Husband: "Dude. Today? You're going to have to clean the house, do the laundry, and eat frozen pizza. I'm going out to get a pedicure, a massage, and a facial. I need to feel refreshed...for when THE REVOLUTION COMES."
To The Relative That You No Likey: "I'm soooo sorry, but I won't be able to attend your
To The Lady Who Weighs You In At Weight Watchers: "I'm up two pounds?! Well, in the grand scheme of things, I don't REALLY think that anybody's going to give a crap about the SIZE of my ass...WHEN THE REVOLUTION COMES."
See? It really works!
And before you ask, the answer is NO.
People WILL NOT really believe you.
But, they won't ask questions, either.
They'll just look at you with confusion in their eyes, thinking... I have no fuggin idea what the hell you are talking about. And they'll pretty much accept your explanation because of the probability that you appear to have gone balls to the wall crazy.
Whatever works, y'all.