What makes your character despair?

A friend\’s cat had to be put to sleep this weekend, and I have been feeling very sad about this event. I care deeply for the friend, and met the cat once, briefly at a party. I realized as I was dancing tango earlier, that aside from the natural sympathy I feel for my friend and his wife, I have been reliving the times I have had to put cats to sleep in my life. I have had cats since I was seven, so there have been a few. What I realized was that I wasn\’t just being empathetic toward my friend, but rather I was having a post-traumatic stress response to hearing about his cat, because my experiences were so upsetting that I am still haunted, and this similar event brought everything back.

I saw this article about the cost of doing repeated service in Iraq, and thought that the parallel between the trauma of a cat\’s death and war were interesting.

As an exercise:
What personal event or events has you main character experienced? Why was it traumatic for them? How does this new event remind them of their past? Is there a way to use a new similar event to create more inner conflict for your character?