There are too many bad things in this world
Have you ever heard the phrase, "Man's inhumanity to man?" to describe inhumane treatment of fellow human beings? It actually should be phrased, "Man's humanity to man" since the option of choosing evil deeds has been on the earth much longer than you and I have.
Having been made in God's image and given dominion over the animals (Gen. 1:26-27), we have superior ability to think, feel and be spiritual beings. With these special privileges comes the ability to choose good or evil. What type of God would we have if He didn't allow us the gift of choice in our everyday decisions?
He would be like a husband who locks his wife in the house when he leaves for work in the morning in order to keep her "safe" and all to himself. Does she actually have the ability to LOVE her husband if he isn't actually giving her a CHOICE to do so? Love is of God (1 John 4:8-7). There is also an opposite force in the world that is evil, and that is Satan. We all have the ability to choose good or evil.
There is a war going on for your very spiritual being and yet you are still given the gift of free will. "For God so loved the world that he gave his only begotten Son, that whosoever believes in him should not perish, but have everlasting life" (John 3:16). God has given each of us a choice to be forgiven for our sins through the good news of His Son, Jesus. The free will to believe and choose a personal relationship with God through His Son is not forced upon you. Have you made your spiritual choice yet?