When I say I need to go... I mean it!

What is with people when you are on the phone with them? If you need to go, then you need to go. If I make a phone call, and the end result is to get an answer to a question... once I have the answer, I am pretty much ready to get off the phone. Why is it that with some people, you have to tell them multiple times "Ok, I have to go now"... and they will still just keep talking. WTF?