The Cheap, Knock-Off Rolex Watch of Emotions

When you think of tension out in the world of physics, you think of a piece of string or wire being drawn taut to the point of near breaking, a large rubber band (of the sort you associate with a slingshot) being extended to such a degree that it will, in the process of returning to its normal state, send a pebble or small projectile flying with great force and delivering itself to a target with a smack.

Tension means something being extended out of shape, a force or pressure being applied somewhere and, in strict accordance with Newton's observations of the behavior of matter, a consequential effect in direct proportion to the density of applied tension.

In the worlds of psychological and dramatic reality, tension continues to apply the equivalent of Newtonian observations to existential and dramatic postures, wherein individuals respond by tensing in reaction to a physical or emotional stimulus. 

A tense person is "all nerves" or "on edge;" a tense dramatic situation is one beset by impending deadlines, sudden and unanticipated disaster, the arrival of a suspicious individual. The individuals who appear in these psychological or dramatic situations responds, each in idiosyncratic fashion demonstrating the emergency modes of persons who have been stressed to some abnormal extreme.

Part of the joy of investigating story comes from the discovery of what normal behavior is, because, whatever it is, the presence of tension allows us to see the difference between the laid-back, mellowed-out was of then, and the tense, emotionally taut is of now.

Tension can be said to represent a force holding in most emotions except fears associated with survival; danger, predators lurking nearby. Coping responses may be driven by panic, urgent messages shouting, "Run! Run!"  Never mind what is being run from.

The point of this stress talk is your observation that the panic mechanism triggered by stress causes your characters to do things they might not ordinarily do when they are not stressed...

...which brings forth the matter of what the characters do when tension is removed or at least allowed to unwind: they become better able to recognize and deal with the feelings put on hold when panic strikes. In some cases, the character has been wound up most of his or her adult life and the emotions now freed come forth at a different age level, with the ironic observation of them, you may only be the emotional equivalent of a knock-off Rolex watch, but at least for a while, you'll keep good time.