Evolutionary Response? in A transparent lockbox

Why is it that sometimes when we are confronted with emotionally challenging and frankly depressing situations, we can feel amazing initially? Like in a situation where you are told you aren’t good enough for someone or something, yet you can’t help but smile and think “I’m free”? Is it destiny and fate being sure to reinforce that it wasn’t something we were meant to experience? Or maybe it is something used in evolution for the sake of survival. Like in the event we learn distressing information, and our brains make sure to send a surge of dopamine and serotonin in order to make sure that we can escape this emotionally unpleasant situation, and then later be able to process it. There are just those things where you experience them, you think you are fine, but then you find yourself miserable, anxious, or distraught in a couple of hours or days. Maybe I’m overthinking the karmic and evolutionary meanings, maybe it is somewhat a trauma response. The ability to dissociate in the face of painful stimuli. Although it could come to bite me in the ass later, I don’t feel too upset in this present moment, in the face of the disappointment of something I’ve been pining for all month. I don’t know if it is for the best or the worst I feel nothing, lets hope for the best.