Does it matter which side of the aluminum foil I use when baking?

I could swear I was told long ago to keep the shiny side out. My wife swears it’s the opposite. Actually, I think she might be onto something. The shiny side should reflect light, and thus heat, slowing down the cooking time. Although, why don’t they just make one side black in order for it to absorb more heat? But then again do we even want to reflect or absorb more heat when we have something in the oven? Couldn’t that screw up cooking times? You know, the more I think about it the more I think the difference between shiny-side in and shiny-side out won’t really make that much of a difference. But then why even make the one side shiny in the first place? I’m so confused. Help me here.
Ow. I’m getting an ice cream headache!