32 And David said to Saul, Let no man's heart fail because of him; your servant will go and fight against this Philistine. 33 Saul said to David: You will not be able to go against that Philistine to fight with him; because you are a child, and he a man of war from his youth. 34 David answered Saul, Your servant was a shepherd of his father's sheep; and when a lion or a bear came and took a lamb from the herd, 35 I would go out after him, beat him and free him from his mouth; and if he rose up against me, I would grab him by the jaw, wound him, and kill him. 36 It was a lion, it was a bear, your servant killed it; and this uncircumcised Philistine will be like one of them, because he has provoked the army of the living God. 1 Samuel 17: 32-36 King James Version (KJV)

The attitude you have when faced with a challenge will be decisive for your victory or defeat. Nobody competes to lose. Everything in one way or another when we enter a combat the most we want is to obtain victory.

In the Christian life, you don't have to settle for being optimistic, but to fully trust that in Christ you are already an overcomer.

When David arrived at the battlefield where the defiant Goliath was going to devour the people of Israel, David already had full confidence that God would give him the victory as he had before against the lions and bears that tried to eat his father's sheep. .

David did not go into combat with the optimism of winning and defeating Goliath. David simply entered with the absolute assurance that God had already given him victory over Goliath.
While it is true, optimism can positively influence things to turn out well in life, however, when we have full faith and confidence that God is with us, we become successful in all scenarios of our life.

Having a winning attitude leads us first that our faith must be centered and developed in God. We cannot trust our abilities and strength, if God is not with us.
When we have a winning attitude and established in God, we can be confident that there will be no giants, no obstacles in life that can defeat us.

In the end David defeated the giant Goliath as one more bear or lion of the pack. David only recalled the mighty acts of God with which he had fought him in past battles.

He who maintains a winning attitude in Christ will enjoy important victories in life and will be successful in everything he undertakes.