We suffer without choice. We do not want to suffer and we try everything to be happy but suffering happens regardless of our wishes, and we can't do anything about it. Why is this so? It is because we have already created the causes for suffering in the past. But where are those causes of suffering? They are within your mind right now, it is the self-centered mind and all the disturbing emotions that come from it. If you recognise this, you will understand that you are responsible for your suffering and that there is no one else to blame. Understanding this you will be able to tolerate difficulties and avoid more suffering in the future. If you want to be happy you must know the causes for happiness. 

-- Garchen Rinpoche