This is one of those, I wonder why questions, that many of us have asked over the years. Just as you may have imagined there is not a simple answer to this age old question.
However, let me give you some possibilities that may help answer the question for you.
Now keep in mind that not all dogs do the circle ritual and it appears that not all dogs do it every time they need to go. If you have a dog that circles it is just part of the norm for dogs.
My pug, Destiny, made me crazy with her circling. Honestly, she circled so much that I thought she would get dizzy and fall over. And it was without fail. I don't remember a single time that she didn't go round and round before finally going to the bathroom. And for her, it was poop or pee, didn't matter. She had to circle.
She was actually the only dog I've ever had that did that so religiously. That's Destiny. Unfortunately, she crossed the rainbow bridge in November due to stomach cancer.
So why does your dog do the circle dance before doing its business is probably still up in the air. However, it is not a behaviour that you should be worried about.
I think probably the biggest issue is for you to help your dog find the exact right location by simply keeping moving until that perfect spot is located. The worst part is getting him or her to hurry so you can get in out of the rain, snow, cold or heat. You get the idea!
Heidi Caccamise is a popular pet blogger and pet product marketer. More of Heidi’s informative blog posts and pet product range can be found at https://peppy-paws.com