My answer to that is: Flip flops are terrible for your feet. Flip flops lack support for the medial arch (the arch that runs from the inside of your foot to the outside) and the longitudinal arch (arch from the toes to the heel). They do not properly accept the forces that are applied during the weight acceptance phase of gait, this is the phase when your foot contacts the surface.

The improper distribution of forces may cause muscle strains, ligament sprains, or other soft tissue injury. For example the lack of support may change your gait leading to an over stretching of the plantar fascia. This may cause heel pain or even a heel spur. The altered gait may also lead to improper weight acceptance leading to ankle, knee, hip, and low back dysfunction.

Please choose your footwear with your feet in mind.