WendyMcElroy.com

Although I do not agree that aspect is as important as substance, this aphorism is particularly needed in our society because manners do not seem to be valued or taught any more. And they are important. I remember how impressed I was with my neighbor because she taught her son to always acknowledge a gift with a 'thank you' note. That level of courtesy is rare and growing rarer. For example, most people do not even know how to apologize...even those who think they know how to do so often get it wrong. They say something like, "I'm sorry I did X but you irritate me so much when you do Y." This blames the other person. Or they say, "I'm sorry but I had a headache." That excuses them from blame. The way to apologize is to say "I'm sorry. I was out of line and I will never do X again. I hope you can overlook my behavior."

I remember how surprised a friend was after consulting me about whether something he'd done to a girlfriend was immoral or a violations of rights. (And, yes, Objectivists actually talk this way.) I thought his behavior was neither. But I added, "it was very rude and purposefully hurtful of you, and I think civility is one of the neglected building blocks of a peaceful society. I think you were wrong and she deserves an apology." Incivility is not immorality, to be sure, but it is closer than I want to come and it impoverishes the society I live in. If you want me to be rude to you, then you need to work to deserve it.
I'm not sure whether good manners "gets you out of any tight situation," as Gracian claims, but it sure will minimize them. It also helps to form the habit of self-restraint, which controls bad behaviors such as losing your temper in circumstances in which you shouldn't.