A new experience for me...

My whole life I have grown up using the expression "Uff dah".  Today I said it as I was picking something heavy up.  The two guys I work with have never heard the expression before!  Can you believe this!  I was just flabbergasted to hear that there are people in this world that don't know what Uff Dah means!  They even noticed that it was written on my Fargo marathon bag I have in the office.  Now they use it numerous times a day...I can't decide if they are mocking me or actually like saying it!