Parenting. We all have two parents within us both in a physical sense, because we need those two people to exist.
(Side note, isn't it great that all your ancestors were lucky enough to find someone to shack up with all the way back to the dawn of time?). But also metaphorically.
Those two parents are 1. The parent you think you will be. Then 2. The parent you will actually become.
Oh yes, when you're fortunate enough to find the one you decide to start a family with you start with the parental planning as well.
Trips to the park with a home-packed picnic, blanket in the sunshine and joyous trips down the slide with your cherub in hand all flash before your eyes, as you stroll the aisles of the baby store lovingly selecting the stroller of your dreams.