Call You RIGHT Back!

When you are in the middle of a telephone conversation and you hear this commonly (mis)used phrase - what image is conjured up in your mind?
If you're like me, you assume it means that the when the person you were deep in coversation with is either finished with the call that bumped yours or takes care of whatever "pressing" issue is so demanding that they will....oh, I don't know - call you right back!
Define "right back." If you're using the Clintonian definition there will be extra "wiggle" room but still I think of "right back" as in the next 15 minutes or so. Right?
Anything past that and you're just sitting around waiting for the phone to ring. Not much time to get into something when you know the phone is just going to ring and interrupt. Yet, too much time to just sit around waiting for the damn phone to ring. You see the trouble. But what to do?
If you inquire as to the approximate time of the return phone call you could risk appearing desperate for the call when, in fact, you'd just like some information so that you can go about your day. You have things to do - phone calls to make! People to call back!!
Or - you say nothing. You let the call come in when it does and if it's not a good time for you - the age-old technology game called "phone tag" begins!