The structure I'm talking about is the one that's inherently associated with having boxes around traits.
The reason I don't use other, scientifically rigorous systems, is because they lack these boxes. Basically, if you can identify patterns between traits and then box somebody, then you can predict how they will behave in different circumstances. This is much more difficult to do when there aren't clearly established boxes.
That being said, I'm generally against boxing things up because things are rarely ever so black and white. I merely do it out of its utility for living life.