It is useless to attempt to reason a man out of a thing he was never reasoned into. Jonathan Swift.I have little doubt that Swift meant this in a derogatory manner. But I take this quote as a bit of positive advice. Many things, such as subjective preferences, have nothing to do with reason, though sometimes we attempt to rationalize such preferences after the fact.
I hate the color pink. Ugly, ugly, ugly, in my subjective opinion. I didn't reason my way into that preference and nobody can reason me out of it. Swift's quote points out that it's pointless to try and that it's a good idea to figure what things are just preferences to avoid silly debates - like arguing about my aesthetic revulsion to the color pink.