In Geneva, I had left my backpack (I was backpacking, so EVERYTHING I was travelling with was in there) minus my camera and some day-travel things, in a locker at the train station. It was one of those lockers where you stick in a coin and you get the key.
Anyway, I put the key in my change pouch and went out with my buddies to take a walk around the city.
About 15 minutes after I left the train station, I realized I didn't have my pouch anymore.
I figured I just dropped it, but I didn't want to go back to try and get the situatoin resolved (for some stupid reason).
I should have, because a few hours later when we went back, my stuff was gone.
All of it.
My pack had two parts: the main bag, and a small day-pack attached to it.
Luckily, some guy found my daypack, which had all my used, undeveloped film rolls in it, so he mailed those back home for me.
So I ended up buying a small backpack (not much bigger than a large purse) and I used that as my main bag for the rest of the trip. It was pretty ghetto.. I was even carrying my stuff around in plastic bags. Hah.