Pride for winning the game of making a large profit, or revenge for being on the receiving end of this same treatment, or for some real or imagined slight, add to the temptation to cheat.
It is a very complex game, with its own intrinsic interest. Love, romance, friendship are trapped within a small window of opportunity: between the initial cheating of a stranger and the final betrayal of the friend or lover.
Love, sympathy, friendship bring with them the feeling of immortality, of the world seen as a whole, rather then individual things which decay and die. But in this game, friendship and love become mortal: they have a time limit. They are lived against the clock. What makes us feel most alive brings with it the idea of death.
The sudden closing of the window, return of hostilities after the interval of peace, depends on this intrinsic confusion for its success. Distracted by the spectacle of timeless love caught in a story with a necessary end, infinite value made more precious by a finite period of enjoyment, the end is not prepared for.
The infinite of love is caught and undermined by the finite profit expected in one round of the game, but in the game as a whole profit is sought without limit, and love is only one limited element among others. Profit is its own end, and preoccupation with its infinite nature diverts attention from intimations of death.