But I do believe in five rules for gracious living:
1. Offer your seat on the Metro to the elderly, the pregnant, or, hey, even someone who looks tired or like they were on their feet all day. The average Starbucks barista makes $8.55 an hour to deal with caffeine-starved self-important morons all day - why not offer her your chair?
2. Bonus round: Offer your seat by merely saying, "Would you like to sit down?" Don't add a justification, like, "You look pregnant to me." Super-special bonus - this gets you out of being thumped when you tell a non-pregnant lady that she looks pregnant.
3. Never leave someone sitting alone in a corner at a party. Middle school is over, and so is ostracizing someone because they might be uncool. Go over and introduce yourself! Unless they're rifling through the sofa for spare change. Because that's just weird. But, overall, five minutes of potentially boring chitchat with a stranger won't kill you. And you might even make a new friend.
4. When you ask a coworker to do something, don't call out 'thank you' over your shoulder as you walk away. Thank them face-to-face. Don't treat gratitude as an afterthought.
5. When you have guests coming over, and they ask what they should bring, ask if they had something particular in mind. They might have a specialty they'd love to prepare for you. Doling out assignments converts your friends into unpaid caterers. Let them do what they enjoy, even if it means a dozen artichoke dips and four tater tot-and-bean casseroles.
In the comments, tell me what etiquette rules you've invented lately. Or tell me I've tumbled off the Cliffs of Nice into the Abyss of Insufferable.