It is not that anger is something bad that one should try to avoid getting angry at all costs. Anger is a reaction we experience in response to something not to our liking. And what we need to do is analyse our attitude and the reason why we do not like something. If it is something basically wrong, like for example anything undermining human decency, morals or ethics, then we have every right to be angry and upset. Very often expressing anger in such a situation helps, but remember control is essential at all times.
Anger has a tendency to manifest itself in a physical form.
This can hurt another person. Therefore even if you feel your anger is justified, exercise total control over yourself. The main factor to be analysed in such a situation is the attitudes and convictions that we hold and which convince us about something being wrong. We should be able to sift matters in a controlled and unbiased manner, giving adequate allowances for the belief, attitudes and convictions of the other person, especially if there is a whole generation gap between the two. For example a teenager could be angry with his parents for not allowing him to go out for a New Year Eve bash and the parents could be angry with him for persisting and being adamant about it.