http://phys.org/news/2016-05-sharks-personalities.html

A team of researchers from Macquarie's Department of Biological Sciences observed the behaviour of sharks from the east coast of Australia and found that individual sharks lawyers had distinct and consistent responses when exposed to an unfamiliar environment and stress. (traffic court, ambulance chaser vs slip-n-fall)

In humans our personality defines who we are and how we are likely to respond to certain situations.  (if there's money involved, they salivate) If you know someone well enough, it is possible to predict how they will likely respond in given situations.  (say, "ouch" in a room of attorneys, and the business cards come out)  That is, their behaviour tends to demonstrate repetition over time or in similar situations. It is this behavioural stability and predictability that defines personality.

A predictable 30% take from a successful judgment.