the four kinds of people you will meet on earth

i can basically categorize people into four kinds.

category 1 - the people whom i like.
category 2 - the people whom i do not like.
category 3 - the people who like me.
category 4 - the people who do not like me.

pretty simple, right? if we can just apply these four simple categories in our lives. the world would be a better place.