I've trained on and off for the years. Probably only 100ish hours of mat time. I'd rolled with mainly white and blue belts, the occasional purple, and maybe 1 brown. Even with that, I understood that there are some serious levels to this.
Then last year I rolled with a black belt. It was like a different game. I'm a big dude, but I could not move this guy. It was like trying to move a car, it just rocked a little as he looked at me with amusement and pity. He did the same stuff I know, just better. And he knew what I was thinking before I knew it. He's got top half guard, and Im fighting for an underhook. As I think, "Ok, he cant choke me with 1 hand, he won't go for the brabo", he goes, "You know I can still sink this with 1 hand, right?".
He did, and he looked bored doing it.