A lot of pets will ignore you, but only a cat will follow you from room to room and check your lines of vision to make absolutely certain that you can see them ignoring you.
theyre not ignoring you! this is actually just a cats way of saying they want to keep you company without infringing on your personal space. its the equivalent of going to a friends house while you both separately scroll through tumblr, even though youre glad to be together.
alternatively the cat could be curious about what you are doing, but shy to make its presence known. either way the cat is paying very close attention to you!