All the happiness there is in this world Arises from wishing others to be happy. And all the suffering there is in this world Arises from wishing oneself to be happy.
ShantidevaWhatever happens, I will not let my cheerfulness be disturbed. Being unhappy won't get me anywhere and will dissipate all my goodness. Why be unhappy about something if you can change it? And if you can't, how will being unhappy help?
Shantideva