If the problem can be solved why worry? If the problem cannot be solved worrying will do you no good.
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?
ShantidevaOne should do nothing other than what is directly or indirectly of benefit to living beings.
ShantidevaAll the suffering in the world comes from seeking pleasure for oneself. All the happiness in the world comes from seeking pleasure for others.
Shantideva