Sometimes I try snapping vertices to the closest neighbour but it doesn't work as the object is always off. I think I'm missing something. I applied all transformations already and the origin is at center. What could it be?

In this gif I'm trying to snap the angled pole to the bottom pole's low right (then left) corner with vertex snap. But as you can see it is off in all cases, even when I try to snap to vertices of different objects.