What is that Human Thinking

This morning on our walk, we saw a cat.  We jumped around, whined, and as embarrassing as it may be, we squealed.  And what did the crazy human do?  She ignored our pleas!  She sped up, tightened up on the leashes and walked with an intense determination.  We communicated "CAT! CAT!CAT!" for as long as we could and she was so disinterested.  We just don't get her.  We love her, but don't get her.