Why are some people persnickety without reason?

I’m very laid-back. I don’t care how someone does something as long it works and everyone’s happy.

But a problem has arisen between me and my dad’s wife.

My dog has been climbing out of her fence because she prefers to be on the lead where my dad’s wife’s dog usually is.

Her dog doesn’t like to be on that lead anyway, I put my dog there and put her dog where my dog usually is and it was fine.
Neither of them tried to escape today.

But she got home and saw my dog on her dog’s lead and went out and moved my dog and then brought hers inside.

I get yelled at all the time for putting my dog on her dog’s lead. Even though it doesn’t cause a problem.

I just don’t understand why if the new dog situation is working…why does she care that my dog is where hers usually is?

And I know loads of people like this. Nothing is right unless it’s their idea or their way of doing it. Even if the other person IS right.

Any insight on to why some people so anal about stuff like this?

I asked her why and she couldn’t give me a good reason. Just because she said so.