What Did You Leave In The Bag/Car?

We've been known to forget things in our bags/cars.  Maybe it was important documents or cell phones.  How about the items that ended up becoming a tragedy??  I have a 'tuna-riffic' story that begs the lesson of never forgetting anything again!

I brought a container of Tuna to work with me----about four days ago.   Like many days at work, I tend to have at least 10 things on my mind, and always seemed to forget to eat the homemade tuna that was festering in my gym bag!  Yes---the gym bag of all things!

What did you end up leaving in your bag/car?