When we're recognizing that Children Have Their Own Path and Purpose (this week's theme), we see them, embrace even the hard parts, stay engaged to support them, and let them make mistakes. To do all of that, we may need to practice not taking things personally.
First, it is wise to understand that our child's behavior really is not personal. Children and teens are actually strongly (and developmentally appropriately) self-centered. They are rarely doing things to upset us! Remind yourself, when things go wrong, that this is not a personal attack on you, even though there may be learning opportunities for you.
Second, after the logical understanding takes root, then we need to work with our feelings. When something happens that you begin to take personally ('Why would she do that to me? Doesn't she understand how much I love her/tired I am/hard I worked on that dinner?"), use mindfulness:
What am I feeling?
As you notice your feelings, you may find it helpful to take some mindful breaths, allowing yourself to come back from stories or reactions to the present moment. If your reactions are strong, you may even need to go for a walk, do some jumping jacks, breathe with long exhales, or sit with your dog for a bit to bring yourself back to center. Ask yourself if you are sure the story/thoughts are true, maybe being curious about other possible stories or explanations ('Maybe he says he hates this dinner because he doesn't care about my hard work, or maybe there's something he really doesn't like, maybe he even just had a lousy day at school.').
As a mom (to 2 teenage sons), wife, and person in the world, I have been on a long imperfect journey. I have made many mistakes, but with mindfulness, emotional reflection, and lots of support I have learned enormously from those mistakes.