When you feed your cats before you feed yourself.
When you stay at home for vacations because you have cats to care for.
When you spend more money on your cats than yourself.
When you only allow yourself a small area on your queen sized bed so that your cats can have the rest of the bed.
When you always leave your bathroom door open so your cats can come in and visit you while you're using the toliet or taking a shower.
When you use a door stopper on your bedroom door so your cats can come and go as they please during the night.
When you have more pictures of your cats than you do of your family.

I'm sure there are many other things that I haven't thought of.