Ephesians 2:10 (NKJV)
Every product you can buy was designed for a certain purpose. But if the product is not used for that intended purpose, then that thing will not be as effective as it could be if it was in fact used for the purpose it was designed for. For example, if you took a nice pen, and put toothpaste on it and tried to brush your teeth with it, you would obviously have less than good results, because a pen was not designed for you to brush your teeth with. To get the best use out of something, we have to use it for what it was designed for.
Ephesians 2:10 tells us that we are God's workmanship, God is the One who created us, and He designed us for a purpose. One of the highest goals any Christian can have is to discover and fulfill the purpose and plan that God has for their life, what He designed them to do. Once we are saved, we are then supposed to do the good works that God designed us to do. Our good works do not save us or earn us some position with God, but once we are a part of God's family, we are then supposed to do the good works that God designed us to do.
In 1 Peter 4:10, it tells us that each of us has received a gift that we can use to serve one another. But, if we do not understand what we were designed to do, we may try to do something God never intended for us to do. By spending time with God in His Word and prayer, by taking advantage of the opportunities we have to serve others, inside and outside of the church, we can all learn what purpose God designed us for and then be faithful in that. True fulfillment in life is found when we recognize God's plan and purpose and then fulfill it.