There is a story I heard long time ago

“A man comes to the race track and bets $10 on a horse.He wins, and bet entire amount again.He wins, and bet entire amount again.He wins, and …you know the drill by now.

So winning he keeps and finally has huge amount …and he bets it again And he loses, loses obscene amount of money.When he walks toward the exit of race track his friend stops him and asks: How did you do today?

Man answers: Not bad, I only lost $10.

 The moral of the story (beside of always setting aside part of your winnings ) is that you can only lose your initial stake and you have to be able to stay with the working trade.