Why are my hardwood floors feeling rough after applying polyurethane?

Roughness on hardwood floors after applying polyurethane can be caused by improper application, such as not sanding the floors properly before applying the polyurethane or applying too thick of a coat. It can also be due to dust or debris getting trapped in the polyurethane while it is drying. Sanding the floors lightly and applying a new coat of polyurethane may help smooth out the roughness.