How to say goodbye on the phone

Why do British people end a phone conversation with a string of "bye...bye now..bye bye..." which continues until they actually hang up the phone?  It sounds like a needy teenager who doesn't want to hang up first!

Is this unique to the UK or have they started doing this in America too?

I wondered that myself recently! (Found myself doing it.)

I think it's a politeness thing. It is less abrupt than the US way but does waste a bit of time!

My mother (American) is Queen of the twenty-minute goodbye.   

Oh, I noticed this recently at work. I feel rude but I usually just say have a nice day good bye.  I was told by my colleague it's just a British thing

I too always feel rude because I feel like I'm cutting the person off! I think it might be distinctly British, but I know plenty of Brits that just literally do a "bye" and hang up ASAP (to the point of actually cutting the other person off - this happened with one of my colleagues last week and she felt really bad and said "oops...")

Haha My husband has one friend who really stretches out the goodbyes. "Bye...bye luv...take care luv...bye now...good talking to you....bye....bye!"  He's a real sweetheart. I think it's funny.