I bought too much

Yesterday I was with my "Thursday" group and I was going to fill the bobbins with embroidery thread. That was the plan for the entire evening (2+ hours). I had 32 skeins of thread and 28+ bobbins. So, there I am comparing the numbers of the threads to my master list and I find I have them all except for one! I bought 31 bits of thread I already had! Why do I do this????? I cannot even say how many times I have bought a second pattern or book. Each time I think how much I must have really loved the pattern(s) if I choose it twice. Now when I see a book or pattern, I write it down and check at home and then go back and purchase. I ended up finishing a piece of embroidery that I have been sorking on--on and off--for a while. Soon I will add the embellishments and make the pillow. Hopefully I will be able to add the picture to my site.