Why do my shoes crease so easily?

Your shoes bend with your feet, which causes creasing. It's really important that your shoes bend - a shoe that doesn't bend would be so stiff it would be painful to walk in. When shoes bend, the materials are compressed, which causes creasing.
Why do my shoes crease so easily?

The Crease Beast Duo

The bending motion of your feet while walking causes your shoes to crease easily.