Christians don't have a monopoly on goodness; believers and non-believers alike can be kind and thoughtful and dedicated to helping others. God has put something of Himself in each one of us, and because of this we each have the capacity to do good.
But does this mean it doesn't matter what we believe? No, not at all. When someone truly commits their life to Jesus Christ, He makes a difference in the way they live. It may be small at first -- but it will happen, because Jesus Christ now lives within that person, and His goal is to turn us away from our sin and selfishness. As the Bible says, we now have a new purpose, because "We are not trying to please men but God, who tests our hearts" (1 Thessalonians 2:4). If nothing has changed in the life of someone who claims to be a Christian, the Bible says their faith isn't real (see James 2:14-17).
But the Bible tells us something else that's very important: No matter how good we are, we are still sinners, and we still fall short of God's standard -- which is perfection. And that's why we need Christ, because only He can forgive us and change our hearts from within.
Don't use the failures of a few as an excuse to keep away from Christ. Instead, humbly face your need of His forgiveness and new life, and by faith open your heart to Jesus Christ.