Causality is the relation between an event and a second event, or the event and the effect. Usually the second event is identified as a consequence of the first, however sometimes it is not as simple as that. In general, science looks at a correlation between to events, and this is often mistreated as causation.
When you deal with emotions and personality traits it is much less defined as to where correlation becomes causation. The type theory by Eysenck says that behaviour is based on biological causation and describes a person based on dispositional tendencies. This is a common theme in behavioural science and often there is seen to be a causation between personality and activity.