In class, we have been discussing panic attacks (I take a medical-based class)
It is said that it's the worst feeling a person can ever feel in his life.
Have you ever had one? If so, feel free to post about it if you want.

If you have experienced these in a certain amount of time at some point in your life, then you may have encountered a panic attack
    * Palpitations, or accelerated heart rate
    * Sweating
    * Trembling or shaking
    * Sensations of shortness of breath or smothering
    * Feeling of choking
    * Chest pain or discomfort
    * Nausea or abdominal distress
    * Feeling dizzy, unsteady, lightheaded, or faint
    * Derealization (feelings of unreality) or depersonalization (being detached from oneself)
    * Fear of losing control or going crazy
    * Fear of dying
    * Paresthesias (numbness or tingling sensations)
    * Chills or hot flashes

(got this list straight from wikipedia)

Among the discussions I've had with other students, one of them was pinned between two heavy furnitures and that caused a panic attack.
And another one was skateboarding and fell on his back and hit his spine very hard to where he had a difficult time breathing
and he thought he broke it and that caused a panic attack as well.
It can be simply getting stuck in an elevator that caused a panic attack or getting lost in the woods when darkness fell.