At one point in time, ramen wasn't Naruto's favorite food.
That wasn't to say he hated it- Naruto just didn't like it as much when he was a kid. If he really wanted to, Naruto could remember times when ramen was just something to eat when it was in stock and there was nothing else that was good.
He doesn't have to try to remember when ramen became the the main part of his diet.
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It's all very clear, the whole event. It was one of his first days at the academy, (the forth one, to be exact) and he'd just poured some kind of glue-like substance everywhere. Everywhere. Students got stuck in it, papers that needed to be graded were covered in it, Naruto later heard stories about the glue somehow getting into lunches and creating another mess entirely.
All Naruto had to do for punishment was clean up, which was easier said then done, as a third of the classrooms were covered in the stuff.
On estimate, it took about three and a half hours to clean, and by then he was irritated, tired, and hungry.
"I'm done, sensei," he'd snapped at his teacher.
Iruka didn't even look up from un-sticking papers when he said, "That took quite a while." He said it mildly, like it didn't matter. Odd, as he'd been shouting at him to "straighten up and quit the stupid pranks" four hours earlier.
"It'd have taken a lot less time if-" Iruka had looked around the room, then at the clock, then at Naruto himself, which caused the boy to stop his complaints.
"Are you hungry, Naruto?"
"What? I-uh... Yeah, actually." Iruka didn't say anything for a moment, then-
"Well, I know it's not exactly gourmet, but why don't we go and get some ramen? My treat."
Naruto had wanted to say something along the lines of, "Ramen? You're right, that ain't gourmet, that's cheap," but he obviously refrained himself because, hey, free food.
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And the whole time at Ichiraku's, Naruto made it a point to vent about how he was going to be Hokage some day, and then no one would punish him for his stupid pranks, and he'd make them clean everything-
Iruka responded with a smile and "Hokage's don't usually go around defacing property, you know."
Naruto had stayed silent for a moment, then shrugged and said that when he was Hokage, he could do what he wanted. Iruka had laughed and bought him another bowl of ramen, and started nagging about how he noticed Naruto spent more time sleeping in class than doing anything else. Naruto hadn't said anything, because he just thought of something.
At that moment Naruto realized it was the first time he had ever had dinner with someone.
It was also at that moment that he realized that ramen was one of the best foods he'd ever eaten.