Have you ever failed at something? There have been a few things over the years that I just didn't get quite right, especially on the first try. Whether it was trying to bake a cake from scratch, trying to complete several miles of running or learning how to sew, failure can really take the wind out of your sail. You feel like a loser, defeated and discouraged by the thought that whatever it was, it didn't turn out the way you wanted it to.
Failure will make you feel like you're stuck. You can't get traction, you can't get any forward movement and it makes you feel ignorant.
There are people who feel like they've failed in their spiritual walk with God. They may have had a "mountain top experience" at one time and tried hard to turn their life around, but then after a few weeks they went back to their old self. Or, life just seemed to get so busy that it got harder and harder to find time alone with God to study His Word and pray. Instead of putting their faults behind them, they can't move forward. People who feel like they've failed are sad and sad people end up being mad people. God didn't wire you for sadness. He wired you for joy! Nehemiah 8:10 says, "..the joy of the Lord is your strength."
Samuel felt like he had failed. Samuel had anointed Saul to be king over Israel only to have Saul make bad choices. God removed Saul's anointing and Samuel probably felt devastated at the turn of events. But God asked Samuel in I Samuel 16:1, "How long will you mourn for Saul, since I have rejected him as king over Israel? Fill your horn with oil and be on your way. I am sending you to Jesse of Bethlehem. I have chosen one of his sons to be king." God basically asked Samuel, "How long are you going to mourn over something that didn't work out? I've got a new plan!"
Nothing is ever wasted to God, even our failures. Why? Because God gathers what is left, which is more than what you started with, and God makes miracles out of it. God is good!
I once read Thomas Edison had 2,000 failed experiments before he discovered electricity. Would you have given up on the 1,999th try? You're not a failure until you stop trying. You can fail your way to success.
God is looking for somebody to bless, even through their failures.