There were 4 SLQ's in this dealer's box that I liked: 2 1925's, a 1926 and a 1929. I took all 4 of them out of the box, put a loupe to them and chose the 1925 that I liked best. I set it aside and put the other 1925 back in the box. I also kept the 1926 and the 1929. Or so I thought.
Apparently, what I really did was that I kept both 1925's and the 1926 and put the 1929 back in the box. Now, that is bad enough. But today when I went to put the coins in my binders, I realized that I had mismarked my list in the first place and I did not need a 1925 at all! So, I ended up buying not one, but two, 1925 SLQ's that I did not need!
This is how I end up with duplicates!