Much the same like we all get depressed - a normal & necessary mechanism that if it lasts for too long no longer works & causes damage.
Oh, sorry, I really wasn’t clear & just randomly regurgitated from my brainhole wrote the thought I thought people (not you specifically) should be aware-ish of (psa, kinda, about how getting depressed is normal and healthy but that clinical depression is something else - but thats hard to explain to people not afflicted by it & using the case of fatigue + your quote seemed like a good place for it … perhaps if I started with “we all get depressed”).
I wrote it after I’ve already seen your explanation (it felt like a reference anyway) - but now reading what/how tf I replied it absolutely looks like Im explaining you basic human stuff.