never believe that the people around you are innocent, cos they never were (I'm talking about adults/friends)
never think that people around you are always the same all the time even after 1,2,3,4,5, ... , years, cos it would never happen.
never believe that when you are good to someone, he or she will be good to you
never ever think that you know someone too well (inside/out), cos you never can
never believe that the person in front of you is his/her real self
never ever be too kind to someone cos you never know when they will take an advantage of you
( ........ )
never expect someone to change bcos of your words/thoughts, cos a leopard never changes its spot
never say you are innocent bcos it is just a nicer term of stupid
never let others take advantage of you cos you will lose out in the end

just be realistic

好人不一定会有好报的
因为这个世界就是这样
不要说别人狠，过分
只能说自己傻
还是让自己的思想变得成熟，现实点吧!