Lacey is a hardcore left brain extrovert.
I'm not much of a Parelli fan but I do like the idea of figuring out your horses personality and going from there. Just like humans, horses have one or a few learning styles that they use a lot but nobody can get the perfect results from every single learning method.
Even though I don't use Parelli, back when I first started with Lacey I did use the horsenality thing to figure out how to get to her, and after a year I'm seeing major results from not pushing her beyond her boundaries (without the ideas from the chart I feel it would have most likely taken me a year to figure out what she needs). Now she shows me how far I can push and we have a much deeper communication, she looks to me for security, quite literally, and she's figured out how to tell me that I'm pushing too hard without blowing up.
It's helped me get to her which I like but, I also feel that people could seriously misuse it.