I didn't mean to design a hat. I'd never even crocheted a hat before until just a few months ago. I tried a couple of patterns that I found online, but none of them were quite what I was looking for. I modified one thing and then another and then ripped back and started over again, and again, and again.
The stitch pattern was relatively easy. I made an afghan years ago with a simple crocheted cable like this one. I no longer have that afghan or the pattern that I used, but I was able to recreate the cable after a few minutes of experimenting.
The hard part was the overall shape. I wanted a beret shape. Not a perky beret, but a slouchy beret. I wanted it to cover my ears, and I wanted to be able to tuck all of my (waist-length) hair into it; but I didn't want it to be enormous. So I crocheted and ripped and crocheted and ripped and set that one aside and started another, and crocheted and ripped some more--and eventually I had it, the almost-perfect slouchy beret.
Once I had the pattern the way I wanted it, I made three; one in a light grey lambswool for myself, and the two shown above for my Etsy shop. The charcoal gray one is made of lambswool, and the brown of merino wool. All three, of course, were made with recycled yarns salvaged from thrift store sweaters.
Now I just need to write down the pattern before I move on to the next project. I'd rather not, because pattern-writing is tedious, but I know that if I don't, I'll wish I had.