The Human Survival Instinct
Before we get to becoming a Sthithaprajna, we need to understand how we developed our survival instincts. Thousands of years ago, humans had to survive against all elements just as animals did. However, over the past few centuries we have evolved into highly civilized beings who don't have to defend ourselves against predators any longer. So our protective instincts have adapted to defend psychological threats, rather than physiological threats. In our day to day lives now, we defend ourselves against perceived threats to our psyche. When someone makes a snide comment, or when we get bypassed during this year's promotions, we're not really in any danger, but our heart reacts the same way as a snail reacts to a finger touching it; it closes up.