Did you always have to train pets for litter box?

Did you always have to go through litter box training with your pets?

I wonder if dogs and cats are just "natural" to use litter box, or if they also gave you a hard time too at the beginning.

Rabbits are certainly not "natural" at it. My cousin had a rabbit and she refused to use litter box no matter how he tried to train her. I was helping my cousin looking for information online, and we tried all kinds of methods mentioned online but none worked.

That came at a price to the rabbit herself. She was locked up in a cage most of the time instead of having her around like a house cat, because she always take a big dump in a corner when she was let out. My cousin even tried to move the litter box to where she took the dump previously, but she still would just do it right beside the litter box. Although, rabbits poop are not wet at all, it was easy to sweep away those little round "balls".