This doesn't seem obviously bad to me... You just have to differentiate times when you have a gut feeling that something's true because you worked it out before, or because of some stupid reason like your parents telling it to you when you were a kid. Right?

I think I can tell apart rationalizations I'm creating on the spot with reasoning I remember constructing in the past. And if I'm creating rationalizations on the spot, I make an effort to rationalize in the opposing direction a bit for balance.