There's a line of people behind me as I walk through a door. Should I hold the door for only the person behind me, for all of them, or for none of them?
Hold the door for the person directly behind you. For everyone else, you have to make a judgment call. If the door opens in and people are coming behind you, it's easy to make eye contact and hand the door off, Purdy says. If it opens out, you'll be removed from the flow of traffic by holding it, "but it probably won't take more than 15 seconds off your day," he says. If you're with a companion, there are all sorts of permutations as to who holds the door for whom, but it boils down to something fairly simple: "People in 'honor' positions should have less contact with doors," says Purdy. "If you're a gentleman on a date, hold the door for your lady. If you're showing a client to a conference room, hold the door for your client. And so on."

The rule for revolving doors is less intuitive, but it usually comes down to sex. Clarence Winfrey, a doorman at the venerable Peabody Hotel, in Memphis, says, "If the revolving door is moving, the woman goes first." But if it isn't moving, the man should try to "give the door a little push before letting the woman go through it first."

Is it OK to help handicapped people through doorways, or should I ask first?
Always ask first. "It's just the courteous thing to do: 'May I hold the door for you?'" says Cyndi Jones, director of the Center for an Accessible Society, an organization in San Diego that promotes understanding of disability. "But don't say, 'Here, let me help you' or 'Let me do that for you.'"

I'm standing in line at the movie theater and the person in front of me asks me to hold his place. A few minutes later, he comes back — with five friends. Should I challenge him?
While it's fine to hold a place in line for one or two people, this person has abused your courtesy. Whether to challenge such a transgression is a tougher question. Purdy suggests a gentle "Excuse me, but the line extends way back there." If that doesn't work, you have two dignified choices. You can accept that others won't always behave properly and understand that the joys of living with people are sometimes accompanied by annoyances, or you can alert the authorities and your bully will most likely lose the tough act.