These words must be on our mind while we are in gambling, don't chase your loss because it becomes worst if you will dig it and trying to come back.
We also must gamble the amount that we can afford to lose, that's how to discipline ourselves from money managing. Gambling is good for entertainment, that's the fact and nothing will change, don't think that it is a source of income that you could be milking for your own needs.

However, to overcome your loss, think about the fun you had and don't mind your loss.  Just relax for a while if you have lose and come back when you are ready.