When adopting you know specifically what your getting and how that dog behaves. Knowing you saved a life might be the most rewarding of all. Not only are you thankful you have a companion, your companion is grateful he is still living. Puppies in pet stores are guaranteed to be bought, just because there're cute, but not every dog is rescued. I know you can't save every dog but one life DOES make a difference.
Many people think dogs that are rescued have behavior problems or are genetically inferior.
That is NOT true. Many dogs are very sweet and just want a home. It all depends on the dog. Some people do not realize the time, effort, love, and money that has to be contributed in raising a dog, and just forget about them so they give them to shelters. But adopting just might be the best decision you ever made.