When we feel frustrated or hurt by someone it can be almost an instinctive reaction to respond with anger. It is part of that fight or flight reaction. On one hand it is important that we feel an emotional reaction. It is that emotion that gets us to respond in ways that can change things and possibly improve things. Therefore, anger is healthy to feel. It is what we do with the anger that is going to have an impact on our relationships and life.
All of us will also, from time to time, frustrate and or hurt others. Is this our intention? Probably not. Even if we do ever want to frustrate or hurt someone, there is a reason why we are motivated to want this. Most of us deep down, hope that others see a good person at the core no matter what we say or do. We want others to understand us. Even if they don't agree or approve, they understand and still see value in us.
If we keep this idea in our awareness when we respond to feelings of being frustrated or hurt by others, we will have a better chance of improving our relationships. Treat others with love and respect while feeling frustrated or angry with them or the situation. It is easier said then done! There are things we can learn and skills we can develop that help us to skillfully respond to our emotions and improve our relationships and life.