Honestly, I never clicked the navigation bar in beamer slides, and I really wondered whether anyone has used it or not. I suspect that most people keep it just to show the pride that he's using beamer...
Anyways, the navigation bar can be annoying sometimes, especially when you have some long foot notes that overlap it. Put this line in the preamble to remove the navigation bar.
\beamertemplatenavigationsymbolsempty