system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does our conscious mind (morality, discipline,..) take a backseat when we are aroused/excited or in a tight situation (like public confrontation), etc.?

For example when you take a vow to abstain from sex or alcohol, etc. for a certain period, if you're very aroused/have cravings, you might relapse at some point.
gpt
Many different modules in brain, do different things at different times. Older, primal modules, necessary for survival, care little what newfangeled expansions to brainspace say about situations *it* evolved to master countless generations before the rest of what is now you ever took shape.

Old modules, never offline. Newer modules, layered on top of older modules. Old modules not *inactive*; *inhibited*. New modules keep under control. Sometimes, new modules lose control. When damaged. When tired. When angry. When scared. When horny. Old modules say: This is what *we* were made for; *give us control*. Engorge with blood. Force control from newer modules. Do their thing.

When situation resolved, calm back down again.