It's no secret choosing to rescue a dog or cat from an animal shelter is one of the easiest ways to save a life. But what some people might not realize is just how profoundly those creatures could go on to repay them.

This touching new ad from the Battersea Dogs & Cats Home in England does a better job than most in showing the impact formerly unwanted pets can have on the well-being of their adopters. The campaign, appropriately titled Who Needs Who?, tells the story of several pet owners who themselves were saved the moment they opened their hearts to a dog or cat, changing both of their lives for the better.