Zen-Buddhism is a hundred times more melancholic, ordinary Buddhism he is too sad for some. What if you were born? You were born on the light, your first thought should be - here's damn. Because Ideally, you had to achieve nirvana and get out of the circuit of rebirths, finally. And since you were reborn, you still have something to correct, which means you still have that in outer order to improve and so on. So since you were born on this light, it means that in fact you are not good enough, since you are still not in Nirvana. Therefore, with this look at life, "no matter how we all here, you know, pull your strap," and the fact that someone in the form of a slave pulls it does not have a principal difference. And what is there in Nirvana? - Freedom, freedom from constant reincarnations, crushing in this extremely sad world. There, in Nirvana, you have no desire, you have no passion. You thirst for so many things in life - you have a favorite cat, this cat will die. You acquire some things, you are proud of your knowledge there, something you learned - when you die, they will die along with your brain and everything will evaporate. The fact that you spent thousands of hours for some reading is meaningless, it will simply disappear. Do you like cool cars? When you won't, then you liked something there or wanted it does not make any sense. All your friends, all your entertainment, how you drank beer perfectly - they hang out like dust on the monsoon wind in the south of Japan. And simply no one will remember when you all will not become that these events were that they were not, all what you wanted you sooner or later you would lose. All that was good sooner or later ends. Therefore, for any passion you are waiting for pain. If you love someone, then you will hurt or from death or from loss. If something borrowed - it means it will hurt from loss. Therefore, any of your rebirth is, in a sense, pain and suffering. Because you again make you want to want and want to achieve, to rush somewhere, experience passion, and Nirvana is freedom finally. Nirvana is finally you can escape from this circle of rebirth and get rid of desires, passion. No more grief. No more concern. No tears, no sufferment, it's finally freedom - what I need.
