The furnace to wall angle is not 'awkward' so much as 'impossible' -- it appears that the back corner of the furnace would most likely be within the wall.
This is basically because the perspective is inconsistent.

* eyes are out of perspective ( though this is somewhat excusable, it would still look better if fixed)
* back wall is out of perspective.
There are two basic guidelines to go by here:
A) vanishing points should fit onto the same line. Usually, but not always, this is a straight horizontal line.
B) If you're using a non-perspective view (this is called an 'orthographic' view, size does not diminish with distance), then the angle on the canvas of any plane along the normal axes (X,Y,Z) should be uniform.
In this case, I suspect you are using an orthographic projection. Your back wall is at an angle which is about 15 degrees off the possible angles defined by the faces of the anvil. Therefore, the furnace is at 15 degrees to the wall, rather than what I suspect you wanted, 90 degrees.
(I also had setup a very quick+dirty illustration of how to make the furnace visually stand in front of the wall, before I noticed the perspective/projection issues. Basically just enforced a jump in value between the wall and the furnace.)
EDIT:
BTW, the floor tiles, they're out of perspective no matter what: the floor is projected in perspective whereas most other elements are projected orthographically. That said I think it's a nice effect, but you would have to redo the projection of most other objects to match it in order to eliminate the current 'objects float above the ground rather than rest on it' effect.