Unfortunately people respond differently to hunger.
Someone I know is trying to lose weight. Problem is, if they go ~100 kcal below maintenance they turn into a stress eater. ~200 below and they are unable to stop themselves from eating 400 kcal worth of food straight or of the fridge at night. All that on top of being hangry all day.
So losing weight means balancing the diet very carefully because that's not much space between eating enough to maintain the weight and eating so little that hunger overrides reason and overcompensates.
For other people going below maintenance is just kinda uncomfortable but easily doable for a couple days. Advice like "just eat less" actually works for them without having to make a whole science out of it.
True. Also don't underestimate your gut microbiome. Those bacteria and fungi can have a distressing amount of control over you and if your microbiome is out of whack it can make it much more difficult to develop decent eating habits.