"If soap is good, then more soap must be better. If we really want things to be clean and stay clean...more soap just isn't the answer."
 
Using more soap usually ends up causing more problems than it fixes. There's a tendency to overuse a good thing, but in reality, when it comes to cleansers...you really can have too much of a good thing.

Using too much soap makes it harder to fully rinse away soap residue. And one of the reasons soap/detergent is so great for cleaning, is that it attracts dirt. This is great if all the dirt is rinsed away from the surface we were trying to clean. But if all the soap isn't gone...then the surface will continue to attract more dirt.