The first edition of Emily Post's famous "Etiquette" book was published way back in 1922.  But her family still updates it every few years, and it's now in its 18th edition.  Here are a few MODERN DAY etiquette tips that might come in handy.

#1.)  Can You Skip a Handshake If You Think the Person's Sick?  Yes, but don't just leave them hanging.  First say hello.  Then say something like, "I'm trying to avoid the handshake thing right now, because I don't want to get sick."

#2.)  Who Gets to Use the Armrests on an Airplane?  If you're in the middle seat between two people, it's acceptable to use BOTH armrests.  But you definitely don't own them, so don't flip out if someone's elbow drifts over.

--If you're in a window or aisle seat, you should mainly try to lean on the OUTSIDE armrests.

#3.)  When Is It Okay to Unfriend Someone on Facebook?  Basically it's a judgment call.  But if they're constantly posting things that make you uncomfortable or embarrassed, it's worth considering.  Especially if they post them on YOUR page.

--But your level of friendship in REAL LIFE should also factor in.  So don't unfriend your mom just for posting a lame baby picture or something.

#4.)  Is Emailing a Thank You Letter Good Enough?  If you're saying thanks for lunch, probably.  But for something like a birthday gift, a HANDWRITTEN note is still the best option.