Well, that just seems to be our nature. You tell someone “Don’t look behind you, but there is a crazy looking guy over there” and the first thing they do is turn around and look. Or you say “don’t open this box” and they won’t be able to stop wondering “what’s in the box?” until they open it.
Thankfully God figured out a way to conquer that nature!
Well it does appear that Eve was tempted....which until satan was thrown out of heaven that wasn’t possible....so our sinful nature came about after the fall wouldn’t you say?