It's easy to go through life holding on to things that are weighing us down - guilt, resentment, doubt and worry. The problem is that when we allow these things in, the negative takes up space and crowds out the good things that should be there.
Imagine that your life is like a container. You were created to carry joy, peace, confidence and creativity. But if you allow worry in, it pushes out the peace. There's not enough space for both. You can't fill yourself above 100% capacity. You have a limited amount of room. If you allow guilt to take up space, that's space that you don't have for the confidence you need.
The reason some people don't enjoy life is because their hearts are contaminated with so many things. They have 10% worry and stress over their job; 12% bitterness because they are mad about an offense; 20% guilt and beating themselves up for past mistakes, and 9% jealousy because their coworker got a raise. They don't realize that 70% of their container is negative. And then they wonder why they don't have joy, creativity and passion. They only have room for 30% of what they should have.
The scripture says, "Give no place to the enemy." That means give no place to guilt. Give no place to worry. Give no place to bitterness. It can't come in and automatically take over. You control what's in your container. You control what you think about, what you choose to allow in. We all have negative emotions and negative feelings. But you have to make the choice, "I'm not going to give this jealousy, this bitterness, this anger valuable space and let it poison my life. I'm going to protect what I allow in me so God can fill me with all the good things He designed for me!"