He had wanted his son back for so long, and then Naruto arrived so suddenly and unexpetedly, that he'd been so overwhelmingly happy and relieved to notice the boy was a stranger.
At times he couldn't see his little boy in Naruto, the things Naruto did, watching out of the corner of his eye, hand in pockets, tight lipped espressions, made Naruto unrecognizable, alien, just wrong, wrong, wrong!
Sometimes he wondered if there had been a mistake, that actaully this wasn't his son, that his little boy, happy, playfull, mischivious, his 'Daddy's boy' was waiting for him else where, somewhere safe and good and clean and kept him trusting and whole.
And he hated himself for it.
Especially now, watching Naruto as he smiles down at Baby Kurama. Minato recognizise Naruto now, in that smile. The smile that hasn't changed since Naruto was a baby. Honest, wide, heartwarming.
Minato leaves them, then, before Naruto can notice he's there.
Guilt. It's consuming him and he won't burden Naruto with it.