1. Being late
Being late for an appointment or a date or a live performance (where your tardy arrival will disturb others in the audience) is a way of saying that you think your time is more valuable than somebody else’s. Guess what? It isn’t. In the age of cellphones — with alerts and maps — you can estimate travel time fairly accurately, by foot as well as by car. (To be safe, give yourself even longer than you think the trip will take.) It’s also important to alert those who might be waiting for you if you find that you’ll be late after all.
2. Not saying ‘Please’ and ‘Thank you’
As a kind of joke — though a joke with a point — some French café owners a few years back posted signs listing two prices for a cup of coffee. If a customer brusquely asked for “un cafÃ©” the price would be several times more than for a customer who requested “un café, s’il vous plaît” — “a coffee, please.” Saying “Please” or “Thank you,” in whatever language, takes less than a second, and makes almost any interaction more pleasant for all concerned — whether or not it actually saves you money. There’s really no reason not to use these phrases, always.
3. Not saying ‘Excuse me’
If you bump into somebody, or need to pass them in tight quarters, or even just find yourself walking in front of them, the polite thing to do is to excuse yourself. Not doing so signals a disregard for others, or an obliviousness to their physical presence or position.
4. Not sending a thank-you note
If somebody invites you to dinner or a party, gives you a gift, offers you a valuable introduction, or just does something nice for you in general, of course you’ll say, “Thank you” (right?). But if what you’ve enjoyed, or received from someone, is significant, you should go one step further: Write them a thank-you note, whether the old-fashioned kind set down on paper and sent by mail or just a nice email. (If what they’ve done for you is really special, you might consider attaching a note to a bouquet of flowers or a bottle of wine.)
5. Not introducing people (or yourself)
If you find yourself in a situation where you know everybody but they don’t all know each other, it’s common courtesy to introduce them. And if you’re the new arrival to a group and nobody does the honors, you should take the initiative and introduce yourself.