mmmmmmmmbye

Have you ever noticed that some people say "mmmmmbye" instead of just "bye"? Where did that come from? I always thought it was just my boss in highschool, but lately I have noticed others. Lots of others. One interesting thing I noticed is that many of them work in the landscape profession, or professions similar to that such as fencing, curbing, stucco work, etc. There may or may not be anything to that. You be the judge.