Quick summary: the answer to the title question is almost invariably “both”, but to move forward with the false dichotomy noted I am going to comment on how anger is often an emotion that we feel for ourselves…though we are often quick to blame something external for our feelings. Though the environment might have done something to encourage distasteful feelings, often it is how we reacted – how we chose to defend or not defend ourselves, which are the source of the deeper and perhaps more significant source of anger.