Naruto first met the Kyuubi on his fourth birthday. He had not met the Kyuubi after being knocked out by a failed assassination attempt, or an angry mob of villagers. He had met the Kyuubi after doing something many small children had tried to do over the ages with varying degrees of failure. He'd tied a towel around his neck like a cape and jumped off the roof in an attempt to fly.
His first reaction upon seeing the massive mound of orange fur imprisoned behind the bars of his seal hadn't been fear or awe. It had been to cheer and happily shriek "Yay! Hokage-jiji got me a kitty!"
It is a good thing that people generally got better at naming things as they grew up. If they didn't, matricide and patricide would probably be far more common. After spending several minutes cheering over the fact that his favorite person had gotten him exactly what he asked for for his birthday, he christened the rather bemused fox with his current favorite word, which was Underwear.
Over the next eight years and change, many people wasted countless hours futilely searching for the ill-tempered sewer dwelling alley cat that Naruto had adopted, if only to make sure it was properly licensed and up to date on all of its shots, especially the rabies shots, considering a few of the comments Naruto had made about the creature.
Then came the night that Mizuki told Naruto about how the Yondaime Hokage had sealed the Nine-Tailed Fox inside of him.
Naruto had been upset for a moment, until a thought suddenly struck him. Underwear, his evil cat who lived in a cage in the sewer was big and kinda orange, and had a bunch of tails. And, now that he thought about it, looked a bit more like a fox.
Mizuki stood in his tree impatiently waiting for the breakdown, waiting for the demon to deny what it was, waiting for the demon to swear revenge either on him for telling him or on Konoha for hating him and lying to him. Any second now. Any second now...
"Wow, and I spent all this time thinking Underwear was a cat." Naruto said.
It is said that the sound of Mizuki slamming his head against a tree could have been heard for miles around.