Imagine a kid named Billy. Billy, being a young kid, doesn't understand that humans and electricity don't mix and therefore isn't aware that, when he sticks something metal into an electrical socket, he will experience a jolt he'll never forget. Like most kids, all it will take is one shock for Billy to lose all curiosity about the effects of electricity on the human body. In fact, Billy, having experienced the bite of the surprised-faced sockets that taunt all who pass their space on the wall, will be quick to inform his friends that sticking a piece metal into something with electrical current is not a good idea. Even though Billy is most likely frustrated that he had to go through the pain and agony of being electrocuted, his friends will be spared from having to experience that same pain if they listen to his wise council.
The same is true for all things that we have experienced or will experience in this lifetime--good or bad. Because we live in a fallen world and we are given free choice, there will be times in our lives where we'll go through trials, tribulations and plenty of pain. There will also be times when we'll make dumb decisions that cause us to miss out on certain blessings that God had prepared for us. These times may not be enjoyable and we may be confused as to why God would allow us to go through them, but, if we allow these "shocking" experiences to teach us and mold us into the people God wants us to be, we can use them as leverage in encouraging others to avoid things that would lead them into similar situations. Not only that, they will also help us relate with and encourage those who may be going through (or have gone through) the same experiences.
Romans 5:3-4 says, "We can rejoice, too, when we run into problems and trials, for we know that they help us develop endurance. And endurance develops strength of character, and character strengthens our confident hope of salvation." The endurance and strength of character that we develop because of the experiences that we go through allow us to be more confident in our hope of salvation. This confidence isn't limited to us alone though; we are able to share this hope of salvation confidently because of the endurance and strength of character that our experiences have provided. Rejoicing about problems and trials because of how they enhance our ability to encourage is a much better use of our time and energy than allowing ourselves to be upset about them.
Are you constantly bitter about the experiences that God has allowed you to go through or do you use them to encourage others around you? It's important to realize that the impact we are able to have on others can be drastically influenced by the experiences that we go through. Even though the hard times God allows us to undergo aren't fun to deal with, the experience that we gain because of them have the potential to be the best tool we can use to encourage others. Don't hide the wisdom that comes from experience. Allow God to use you, regardless of whether or not you feel useable, and allow the experiences you've had to enhance your ability to encourage others.