Think about how glue actually holds two things together. It is not really about how rough or smooth the surface is by itself, it is about whether the liquid adhesive can spread out and cover the surface completely before it hardens. When a drop of adhesive is placed on a surface and it flattens into a thin, even film instead of forming a bead, we say the liquid is wetting the surface well. Good wetting means the adhesive gets into every tiny irregularity of the surface and forms close molecular contact with it, and that contact is what gives the bond its strength. A surface with high surface tension on its own, or a friction free surface, does not guarantee this spreading. So the property that really controls whether an adhesive will bond properly is good wetting.