You pay a price for every profit you take with time and effort required to obtain it. Not to mention the years of experience upon which your knowledge and system methodology have been constructed. The slippage, and getting knocked out on a winning trade by one tick have a cumulative mental attrition that can only be offset by constant profits, vacations and other interests not market related. Time is the most valuable commodity in every person's life because each person knows he only has so much of it. To use time wisely creates more of it. To use money wisely creates more of it. It is ironic that man is the only animal that knows he is going to die, and the only animal that laughs. There is probably some profound message in this irony, related to trading.