Rain is like an old college friend. It's nice to see until it starts to get in the way.
Yes, rain is very important to this planet. Plants need rain. Animals need rain. The oceans and the rivers need rain. WE need rain. But what we don't need is a bunch of rain getting in our face when we're trying to figure out if "the left by the light" meant the left that's at the light or the left that's right after the light.
So that's why a good pair of wiper blades is so important. Because wiper blades are like bouncers for your windshield. They take the rain you don't want to see and politely move it to the side as you pass.