I've pulled up a few "lost" anchors over the years, but one sticks out in my mind very clearly...
While trying to entertain a GF on an overnighter, I went to toss in the stern anchor (we were anchored up to a tule berm), and in my rush to get things "started", I neglected to make sure that the anchor was attached to the line.
Yep, you guessed it! My danforth and chain was tossed into the drink without a line attached! D'oh!

Even though I was only in about 7' of water, I wasn't going to spoil the mood by jumping in after my mistake.
Oh well, on with the evenings festivities!

A few months later, I was fishing in that same spot (a popular "multi-purpose" location, hehe) and I hooked into a snag. After pulling for a bit, I thought it was a lost cause, but I did get some movement, so I kept trying.
Low and behold, I saw my hook attached to a chain! I reached down and grabbed a hold of it and pulled it up.
It was an anchor!

I then realized that it was MY anchor from the previous event!
I had a smile on my face! (for the SECOND time)