Used to go for perfectly smooth surfaces every time. A post from @joelmoore a while back made me try a bit of texture, and it actually works way better. The material grabs on instead of just sliding around. My last project held up without any peeling.
Ever think about how the texture might help with paint drying? I had a spot that was too smooth and the paint just pooled up, stayed tacky for days. A light sanding gave it something to hold onto and it dried way more even. Not just about the final stick, but how it gets there.