I get angry when I find out people have been slandering me behind my back, especially people who are supposed to be my friends.Mr Fisher said anger can be expressed assertively, aggressively or in a passive-aggressive way. It rises within us when our need to be valued, respected and appreciated is threatened, he added.‘Another reason we get angry is because of the expectations we have,’ he said. ‘I have these assumptions that I make about how you should behave or what you should say or what you should do or how you should treat me.’He divides those who are angry into ‘imploders’, who bottle up their anger inside until it eventually boils over, and ‘exploders’, who blow up immediately but return to normal after a five-minute rant.