Thanks for the help, that got me one step closer but it's still not working.

Yes, I tried using the edit pivot function in the tool settings before and that didn't do anything useful either. I forgot to mention that.

Using the j key did help me set it to 45* though so there's that. But, amazingly, once I've edited the pivot point to 45* offset, as soon as I click on the object again the pivot resets itself!!!! I just. Want to scream. At the top of my lungs. All day.

What I find really lovely is that if I reposition the pivot that change is persistent, but if I rotate it the change doesn't stick? Why would one work but not the other??? Why does nothing that I need ever work but everything immediately adjacent to what I need does seemingly just to rub my face in the thing I need not working???

Anyway, here's some screens of what's happening.

Edit pivot:


Move pivot. The change is persistent. No matter what I do, the pivot always stays here, unless I got back into edit pivot.


So can someone tells me when I do the exact same thing but with rotating the pivot instead of moving it, this happens:
Edit pivot, and rotate 45* using "j" (thanks):


Exit edit pivot and the move manipulator is exactly where it's supposed to be:


But as soon as I click anywhere or do anything:


The pivot. MAGICALLY RESETS IT'S SELF.

So now I can make it LOOK like the pivot is at 45* but anytime I do anything it jumps back to 0* and I can't even take the first step of making this model. STILL.