How you show anger was taught to you long before you had any say. Some households raise their voices and forget it by supper, others go quiet for three days.

What the research says

In a survey of 335 hospital nurses, rigid beliefs about how other people ought to behave, along with a habit of dwelling on slights, predicted whether anger got bottled up or came out destructively. Held expectations shaped the form the anger took. It was cross-sectional and in one profession, so it shows an association rather than a cause.

Strength of evidence: one line of research. A single study, or a theoretical account.