A cool person is someone who has most of the following characteristics:

They like themselves
They know themselves (not the same thing as #1)
They have a relaxed attitude toward life
They are open and accepting toward others
They have the guts to take a stand
They are honest but not hurtfully so
They dress in an intentional way, even if that way is to seem unintentional
They know interesting things and/or have interesting habits
They are anti-authoritarian
They stick up for those who aren’t so cool :-)