All parents lose their tempers sometimes. If it does not happen regularly it will not hurt the child. It affects the child’s development if the interaction within the family is often negative, critical, or unpredictable. Psychological and physical abuse harm the child, and that is why it is forbidden by law. Everyone can learn to regulate their feelings and behaviour for example like this:
Learn to recognise the feeling (e.g. anger or annoyance). Accept the feeling and think about where in your body it is located (e.g. faster breathing or heartbeat, headache). Think about what is causing the feeling (are you tired, stressed, busy, hungry, has something unpleasant happened). Try to calm down (take a deep breath and leave the room for a while if you need to). When you have calmed down you can return to the situation. If you have already lost your temper you should explain the situation to your child and apologise (“I got really angry and said things I didn’t mean. I’m tired and need to get my work done. I apologise for shouting at you.”).