Cortisol is a stress hormone – very addictive. Serotonin is a "happy" hormone – non-addictive, highly sought.
When I don't tell the truth, the whole truth, nothing but the truth, my body stresses, and I am under the influence of cortisol – which, over time, becomes my norm. Even when good things happen, I cut it short by worrying – about something, anything, everything!
When I was in grad school, I was taking double the recommended hours, had 2 part-time jobs, and was a single mom. I was mired in cortisol (and didn't recognize it). Even when I aced an exam, I sweated about my course grade. The lie that cost me peace of mind (and lots of cortisol) was that I HAD TO MAKE A 4.0 GPA (or else my life would be less than optimal > dismal > failure). Post graduation, my body took nine months to detox from the stress (cortisol flood) of my mental drivenness.
On the other hand, when I fully admit the whole truth about my life and what matters most to me, I feel grateful for having such good health, for all the special moments with my daughter and her family, for the warm connections with my friends/clients, and for my faith in the Ultimate Goodness of Life – then I experience peace, satisfaction – a serotonin flood. Sound Pollyann-ish? It's not that I like everything that happens, but weighing the gifts of my life against my challenges – no contest!
The past is over. It has delivered me to this moment. The future isn't real yet. I am free to effectuate my life going forward however it makes sense to me in this moment, responding to life as it unfolds, absolutely knowing that Life/God/The Force is "For" me. Because IT IS.