Anyone who you interact with in some way replaces you.
If you go to a restaurant, the chef there replaces you, if only for an evening, as the person who cooks your meals. By default, you do everything for yourself – all other interactions are acquired.
If you work for someone else, you’re replacing yourself with them as your boss. If you hire a nanny or use a daycare, you’re replacing yourself (at least some of the time) with them as the caregiver of your children.
It’s not a bad thing. But it’s a good reminder – always replace up. Always use someone better. Don’t replace just to replace. If you have to replace yourself, do it with someone you admire.