Eating losses. Seneca, Epistulae 1.1.4-5

Here, at the close of his first epistle, Seneca offers his principle ethic: approach every situation knowing what you must lose--what sacrifice the goddess Fortune demands here, and what resources you have to meet her (chiefly time). If the stakes are too high, don't play. Time is too precious to waste on games you cannot afford to lose. You can hear me read this passage <here>.

Interrogabis fortasse quid ego faciam qui tibi ista praecipio. Fatebor ingenue: quod apud luxuriosum sed diligentem evenit, ratio mihi constat impensae. Non possum dicere nihil perdere, sed quid perdam et quare et quemadmodum dicam; causas paupertatis meae reddam. Sed evenit mihi quod plerisque non suo vitio ad inopiam redactis: omnes ignoscunt, nemo succurrit. Quid ergo est? Non puto pauperem cui quantulumcumque superest sat est. Tu tamen malo serves tua, et bono tempore incipies. Nam ut visum est maioribus nostris, sera parsimonia in fundo est. Non enim tantum minimum in imo est, sed pessimum remanet. Vale. 

You will perhaps ask what I do, what active position I take for myself as I offer you these injunctions. I will confess it freely: whatever befalls the wanton man who nevertheless minds his business carefully, that I reckon as an abiding expense. I cannot say I shall lose nothing by it, only what I shall lose, and why, and how—enumerating the causes of my poverty. This happens to me, and to many others whose reduction to indigence cannot be attributed to their own vice. Nobody comes to heal the lack that all excuse, as a price of doing business. What is the point, then? The man who is content with whatever remains to him, however small it may be, I cannot deem a pauper. As for yourself, you should keep your business as though you were in bad circumstances, and then you will begin to prosper. For as our ancestors noticed, thrift is too late when you have all but drained the cup. In those dregs you will find not merely the least solace, but the worst. Farewell!