You learn to define what is good based on your experiences. No matter how good someone is they are still human.
Only God is perfect. The Bible says in 1 John 5 that He is light. Darkness cannot live in the light. Because He is light no darkness or evil can come from Him.
Many people struggle with why certain things happen. All I can say is that even the worst, most horrible things God will use for good.
Everything, the good and the bad, happen in your life as part of your journey for a reason. As followers of Jesus we need to remember that because God is good His plans for us will always lead to what is good.
We are to taste and see how good He is. His Word is like food for the soul. You can find all kinds of guidance for so many things within the Bible.
Knowing He is good and His plans for you lead to great things, find refuge in His goodness. He alone can bring you joy and blessings in abundance.
Will you choose to focus on your hurts, difficulties, and worries it will you trust in His goodness to see you through?