What does it mean when soap doesn't wash off your skin?

When soap doesn't wash off your skin, it may indicate that the soap has formed a residue due to hard water, which contains minerals that bind with the soap. This can prevent the soap from easily rinsing away. Additionally, if the soap is overly thick or has certain additives, it may also cling to the skin. In some cases, it could simply be a sign that more water is needed to effectively rinse off the soap.