In what was once a civilized society, we have deteriorated to the point that many individuals are so wrapped up in their little world(s) that they no longer consider how their actions affect others.
Inconsiderate road bikers, walkers with cell phones, walkers/joggers/riders with earbuds or earphones, dog walkers with extended leashes...the list is endless. Welcome to our modern equivalent of the wild west, the multi-use path.