Another way to view this: You do not enjoy feeling guilty, and because you believe the truth would hurt your mother in law's feelings, you've decided that avoiding this pain is worth more than giving her that truth -- even though that truth might actually, in the long run, cause her to improve her knitting skills. I'm not saying that the above is true, and if it is, I'd bet dollars to doughnuts that you wouldn't be doing it on a conscious, purposeful level. But it is, certainly, a way to see it. I suspect both stories are true to some degree.
Your statement was "People rationalize it away because lying makes their lives easier." My counterexample was one in which my lying makes my life demonstrably harder. You disregard that and instead decide that I "do not enjoy feeling guilty" and further, I lack the self-awareness to make this choice on a "conscious, purposeful level." In doing so, you disregard my statement that "I don't enjoy lying." I'm in a lose-lose position - By your assertion, I do not enjoy feeling guilty. By my assertion, I do not enjoy lying. To further use your assertion, I probably feel guilty that I'm not "causing her to improve her knitting skills." No matter how you slice it - my arguments, your arguments, anyone's arguments - I lose. The only question is by how much. From an emotional standpoint, however, my mother-in-law either loses or wins. So I choose "big loss" for me in exchange for "mother-in-law wins." Lying doesn't make my life easier. It makes it harder. You are, again, wrong.
It's like you have five interpretations of everything I say, and are just determined to pick the one that is the most insulting to you, and then frame it as what I actually said. Why do you enjoy doing this so much? That depends on when you choose to end the story. If you end it in the moments after you tell her how much her sweaters suck, then sure. However: You don't think it is possible that immediate pain would give way to eventual (but far greater) pleasure, when she no longer is a bad knitter, or has, instead, found something she really is good at? You don't think it's possible that she may eventually, at some point down the road, come to thank you for setting her straight, and bond with you more securely due to your honesty? If not, then... well, that's interesting, I guess. Yes yes, I know how much you enjoy saying that. Good on you, here's some more internet points. Gotta admit, though, I am surprised you are so ready after such a relatively short cool-down period.You disregard that and instead decide that I "do not enjoy feeling guilty" and further, I lack the self-awareness to make this choice on a "conscious, purposeful level."
From an emotional standpoint, however, my mother-in-law either loses or wins.
You are, again, wrong.