Not only for the (hopefully) obvious toilet training reasons, but also a lot of cats I know like to attack shoes (especially open toed shoes/sandals/jandals that are being worn). One of our cats would often be found with her head inside a shoe when she was a kitten, now she reserves it for only stranger's shoes.

And NEVER sit down without checking behind you first. Even if you know the kittens are in a different room still make sure you check. If you don't whatever the distance, no matter how many shut doors they can and will get to that chair (or where ever you are planning to sit) before you sit down, ready to sink claws/fangs into whatever part of your anatomy they can get to, because THEY WERE SITTING THERE FIRST.

Apart from that though, cats are lovely.