If you lose a competition, you’re not as good as your opponent, and when you win, you’re better than them.
There are many situations in which you won’t able to compete on the same level as others. They are better than you—more practiced, more fluid, with more of a grasp of the game you find yourself playing. Why get frustrated in such a moment? Why, if they are so much better than you, and you are trying your best, should you become frustrated?
A loss is only a strike against your pride. The only way you can be damaged in friendly competition is through your ego. Don’t let your ego shine through in any contest or any situation, for that is how you’ll get sorely defeated. Take solace in your ability to work hard and improve, not in your strength compared to someone else.