The worst one that me and my wife have found in our relatively short time caching was just a couple days ago. Somebody decided to place an ammo can on the concrete foundation of a rural water tower in a well farmed field 10 feet from the road. As if the hide itself wasn't lame enough, when I opened it up I discovered a half empty bottle of power steering fluid, a flyer for a hand tool company, and a couple other just plain stupid items. I think the worst part about it was that when I went to log the cache I found that the power steering fluid and tool flyer were ORIGINAL CONTENTS! along with a USED can of chewing tobacco. I'm still upset about this one.
My wife and I have run into a slew of badly stocked caches, but this one was the worst. Our motto is trade even or trade up... If my son wants a toy car out of one cache, I will leave an equally valuable children's toy. Usually we try to trade up, just to give the local caches something worth while.
I just don't get it.