Children doesn't have the thought process same as an adult which always causes a communication and relationship issue, aggravating the parent and exhausting them. To build a healthy relation its best to give them what they need while also not giving them at all. Let me explain, a kid is not listening to you and screaming, instead of getting angry stay calm and distract the kid that might attract his mind eg something shiny, blinking or if a teen is angry try to understand what's the root for causing their behavior, after they are calm, try to find a middle ground instead of just rejecting what they are asking for. make them understand that what is the reason behind your rejection or No. You are an adult, you can reason but the child cannot, you need to lower yourself to their sense so they can understand why you are doing what you are doing. Eventually becoming their safe space. But remember It's step by step and the result just doesn't show in a day.