You are supposed to wear every watch like that. It's no secret. But some arms are simply shaped in a way that the watch tends to slide towards the wrist/hand.
I don't like having my buttons on the opposite site of the wrist either as you then cover the screen when operating the buttons or the crown. I strongly oppose this being the correct way to wear it, as some people proclaim. Actually, one of the reasons I got the Ultra is the button/crown guard. It minimizes the risk of accidental button presses, but they do still happen.