why is one side of the cube different? (and behaves differently)

Why is it that in edit mode, one face of the cube looks and behaves differently?

When I have extruded a few times things don’t behave as I want, and the two sides of the cube behave in different ways, unpredictable to me.


you mean the greyish face
this looks like the last selected face

that’s all it is last selected face!
always been like that
don’t worry about it it is only in the viewport

happy blendering