When one straightens two (vertical or horizontal) lines the other lines often are not straighten

[Wolfgang ([ Win10, PL+VP+FP, Nik7 / 3.3 ])]

@George

My brain says the top of the building, which is further away, must have a smaller magnification as the bottom, which is closer.

Right – and if it is not as ‘expected’, but all leveled (all vertical lines parallel…), it may look wider at the top because of your assumption.
A way to handle this is to let the vertical lines slightly converge until your perception tells you “right”.