and what am I supposed to do with this?

Before Nell arrived to my place, I had bought some generic toys for fostering a dog (rubber chew bones, tennis ball, rubber ball). Never did I imagine a Boston Terrier that didn't like to play fetch... Nell doesn't like the tennis ball... Doesn't know what to do with it... She won't even attempt to chase it. This is another reason why, I think, she's a cat...