People get angry because they are hurting, they are not at ease. 
But if we are happy, we can never get angry at someone else; it is only when we are depressed, tired, frustrated, having a hard time; when we have got some sickness in our hearts, that is when we can get angry at other people. 
So when someone is angry at me I feel compassion and kindness towards that person, because I realise that they are hurting.

Ajahn Brahmavamso
Perth, Western Australia
1990