"I'll call you back"

90% of the time this means 'good-bye' when a person is trying to rid of someone on the phone. With the kind of person I am, I usually expect that call back. Every time though, I end up waiting for nothing. I've come to despise that phrase. If a person has no intention of calling back, then why say that in the first place? Couldn't they just be decent enough to say 'bye'? I suspect the only time a person actually means that they're going to call back again is if they say "I'll call you RIGHT back." Whatevs. People suck.