When I start manhandling expensive British cars around mountain highways and wooing the ladies. *shiny teeth*
You know, to the best of my knowledge and understanding, there's both positive and negative connotations to one's shadow.
On the one hand, negative, when one is under protracted stress, coping strategies ultimately break down, and the person begins to act entirely unlike themselves - for example, my ENFP twin begins to exhibit behaviors seen in ISTJs only exaggerated and stripped of their merit, so what you have is everything bad in an ISTJ being used by someone who is the least like an ISTJ. This is under severe stress and total breakdown is imminent. She becomes comfortless, implacable, controlling and cold.
On the other hand, positive, when my ENFP twin is NOT under terrible extended duress and she's able to unconsciously access her shadow, she really comes through. She exhibits traits seen in ISTJs that are their strengths - steely resolve, decisiveness, organization, consideration, ability to see into the near future and set plans, covering every base. It's astonishing to see it working underneath her ENFP exterior, almost like a viral program running quietly in the background.
In other words, when you're exhibiting your shadow, it's either a good thing, like exercising a weakness, or it's very bad, where you show all the good things of a shadow type through a warped mirror that destroys the original context of the virtues.