What Kind of Business Makes a Living Off of Poop?

Have you ever had to train a dog? 

Well if you've trained dogs before, then you know in the early stages how frustrating it can be. 

I've trained many dogs before. Let me tell you, its the most grieving thing to see your dog poop on the floor...

 You spend so much time indoors, why would you want poop on the floor? 

Why would a dog want to spend time around it's poop? 

I may not be able to clean poop off your floor, but I can keep your lawn unsullied. 

You may call it a "crappy" business if that helps.