People are giant jerks to each other all the time, everywhere, and it's totally lame! Here's a guide that might help.
People act like jerks to their friends...
Source: i.imgur.com
Source: http://24.media.tumblr.com/tumblr_m4enn3RmPq1qdlh1io1_400.gif
Source: gifs.gifbin.com
People don't respect authority figures.
Source: i.imgur.com