Let's delve into the psychological for a moment...
In MBTI, you have the theory of functions. Each person has four functions that they use as ways of dealing with day-to-day life.
Depending on the type you are, depends on the kind of function you most rely on and then the auxiliary function you use typically in tandem with your dominant function, and then the one you used when stressed (tertiary), and then the emergency one which normally manifests itself in a negative way because you haven't had much practice in using it. Here are the functions for every type:
Now what does each function mean? Here's another handy chart:
So sometimes when you're really stressed out and have no idea what to do, you start grasping at straws and you try to protect yourself and get yourself back to a mental state of normalcy. Sometimes this can cause you to slip into a Dominant/Tertiary Loop.
This doesn't happen every time you're stressed out but it happened to me in February and it kinda freaked me out so I did some research.
My function stack is Ne Fi Te Si. So when I looped I was solely relying on Ne and Te. This isn't good because my tertiary function isn't that well developed. So what happened?
Basically, my inner feelings and values I shoved deep into some abyssal vault inside me and started dealing with the source of my stress using completely objective logic no matter how I felt about it.
So I was spouting out ideas of how to fix my problem via Ne and approving them via Te instead of Fi.
I was forcing myself into a robot-like mode so I just quickly dealt out "solutions" with hard logic, not even caring how they would affect me or anyone else later. Te was the BAU5 and was making all the decisions because no one else was contributing (from my perspective).
Thankfully the situation eventually resolved itself but my Fi came back with a vengeance and I fell into this weird despondency and guilt.
So no matter what type you are, remember it's vital to round out all your functions so you don't slip into an unhealthy tertiary loop.