​Yes, indeed they do. But it’s important to understand what “go bad” actually means. Interestingly, if someone forgets about God, meaning they turn from God, they may still have a so-called “good life” as defined by the fallen and sinful world. Thus, an atheist might become very wealthy, and be popular and successful in a worldly way. But if they lack God, while gaining the whole world, the condition of their life is still quite bad from the perspective of truth and regarding true happiness.  
 
On the other hand, if the question simply means that you do not actively think about God for a moment or two, but still love Him and have faith, that’s different. God does not punish us just because we forget to think about Him all day, every day.  
 
Let’s look at that question with some analogies to better answer it:  

•  If a fish were to forget to live in water, would things go bad for the fish?  
• If a person were to forget about eating, would that cause a problem?  
• If a car were to be without fuel, would that make the car stop?  
• If a plant were put in a closet without any light, would that do harm to the plant?  

Of course, the answer to all these questions is “Yes.” A fish is made for water, humans need food, a car needs fuel to operate, and a plant needs light to survive. So it is with us and God. We are made to live in the life of God. Therefore, if by “forgetting about God” we mean we separate ourselves from God, then this is bad and we cannot find true fulfillment in life. If this continues unto death, then we lose God and life for eternity.  
 
The bottom line is that without God we lose everything, including life itself. And if God is not in our lives, we lose that which is most central to who we are. We lose ourselves and fall into a life of sin. So don’t forget about God!

This is a question we should ask ourselves every day of our lives! The answer to this question is never-ending.  
 
It’s true, we are made to be saints. God made us to be one with Him forever in Heaven. We call this holiness, sanctity or saintliness. But how do we become saints?  
 
First, we seek the truth. Truth is discovered by faith. Faith is not just believing in something we cannot know for sure. It’s not just wishful thinking. Faith is knowledge. Certain knowledge. We ultimately obtain faith by allowing God to speak to our inner consciences and reveal that which is true. This happens when two things are present. First, we engage our minds in the truth, such as in the Scripture, the Catechism of the Catholic Church, the teachings of the saints, etc. Second, reading the truth is not enough. We also need the “gift” of faith, meaning that when we hear the truth, God needs to confirm it as “true” in our consciences. God’s voice first revealed the truth through the Scripture, the Church, or the saint, but then God tells us in our souls that this is His Truth. When this happens, we must believe. When this happens, we are gifted with faith. We know, with deep interior certitude, that which God revealed.  
 
Second, this process of coming to know the truth in faith is strengthened by prayer. When we pray, it’s like adding fuel to a fire. The fire, which is faith, grows in intensity. As it grows in intensity, we grow in faith.  
 
Third, we must live what we come to know through faith. This is an act of our wills. When we choose to live the faith we come to know, we grow in charity, holiness, and saintliness. We become saints.  
 
Though this is a greatly simplified explanation of the path to holiness, it should point you in the right direction.