How to handle an MIA responder (and what to do if you're one yourself).

If you've ever had a friend who waited until the last second to RSVP to your party—or you've been the one who has neglected to respond—you'll want to listen to this week's episode of "I Want to Like You," with host and Real Simple editor Kristin van Ogtrop. She's joined again by Tina Gilbertson, a psychotherapist and author of Constructive Wallowing, and Jodi R.R. Smith, founder of Mannersmith Etiquette and author of the From Clueless to Class Act book series, to discuss all of the etiquette rules surrounding party invitations—whether you're sending the invite or opening it. According to Gilbertson: Some people aren't really wired to RSVP. Maybe they have trouble making decisions or commitment-phobia, or are trying to avoid conflict by failing to RSVP. "It's a misguided attempt to protect the person from hearing the word 'no,'" says Gilbertson. Knowing this might not help—it's still incredibly frustrating to be a host with a few guests who refuse to let you know their plans.

In the world of the Internet, there is a new invitation: the Evite. With this technology, the host can see if you're sitting on the invite. As a host, you shouldn't obsessively check the invite, says Smith, but as a guest, you should respond as soon as you know your plans. Smith suggests hiding the guest list if you think people will wait around to see who else is responding to the party.

What if you do have to respond "no?" Less is more: Smith advises providing little information as to why you can't come. A simple, "Sorry I can't make it!" is enough.

For more etiquette about RSVP (like: what to do if you respond way too late, or how to track down guests who go missing), listen to the full episode below, and don't forget to subscribe on iTunes!