And yet, despite this defualt position happening over and over and over again, you haven't. So maybe this default position is actually protective. It could almost be seen as a self-soothing technique, similar to cutting or drug abuse or bulimia. After all, once there's a definite plan to end the pain once and for all it does become a little easier to cope moment to moment, doesn't it? The feelings become less intense, then over days they return to baseline, then life can continue on again.

Until the next time (which is every bit as intense as the last).

When you can hold on to the cycle or pattern once it is activated, it becomes much less scary and much less intense. It starts to lose its hold on you.
Instead of being swept up by the roller coaster you begin to be able to observe it. Then instead of just observing it you begin to be able to apply the brakes a little. Eventually you can pull the emergency brake and hop off the roller coaster altogether as soon as the ride begins.