[header] How to remove a band aid painlessly [title] Soak the bandage in water. [step] You've probably had the misfortune of coming across someone's used bandage floating in the gutter of a public swimming pool, and therefore are aware that exposure to water weakens a bandage's adhesion to skin. [substeps] No, don't go to your public pool. 
Soak in the bathtub for a bit, and then try removing the bandage. A leisurely shower may work as well.