I linked to one of this guy's videos last week.

As I said last week, I don't agree with him on everything, but a couple of things he says strike a cord with me.  And this was one of them.

I think he's right about people spending too much time with the beginner textbook, and in fact I now realize this was the major reason I never got to an advanced level in Japanese.

Not that I never made any progress in Japanese.  I did alright--at the peak of my studying, I think I was upper-intermediate level.
But it took me several years to get to that upper-intermediate level.
I had friends who reached the upper-intermediate level very quickly --in about 2 years.  By contrast it took me about 8 years to get to that same level.  And I never reached an advanced level (unlike many of my friends).

In fact, during those first couple years, I developed a reputation among my colleagues in Japan for not studying Japanese seriously.
That was unfair.  I actually spent hours and hours writing kanji or doing grammar drills in my textbook.
But, I was very anal retentive about it.  In each unit of my textbook, I wanted to master everything perfectly before I moved on to the next unit.
As a result, I spent ages going over and over the beginner textbook, and never really got to the more advanced material.

At the time, I thought this was how it was done.  Build up your basics firmly, and then you'll be better able to tackle the advanced stuff when the time came.

Even after I realized I was falling between in many of my friends, I still stubbornly stuck to my method, believing that in the long run I would come out ahead.

But it never worked out that way.

 I now see that I was wrong.  The way to succeed is to seek out as much language input as possible--even input at an advanced level.
Then, once you've pumped yourself up full of input, go back and consolidate your grammar.

In my own classes, this is one of my justifications for using authentic material (like movies, songs and poems) even at an elementary level.