Questions

I have a question... How can a person be truly happy? Or how can someone be truly sad? What builds up what a person is? Is it what they do, or their personality, or their happiness vs sadness? And if true happiness comes with being in the world but not of the world how can you block your self from wordly things when its all around you? But then my mom says you dont need to get rid of all of it like tv and the internet you just need to moderate it. But how do you moderate it? Why is this life so complicated? Am i really strong enough to overcome all the challenges that i face? So many questions and so little answer.