Very Right. I have come to the conclusion that it is mostly Emotions/Feelings over Intellect/Rationality though they are interlinked together. To suppress the former and give free reign to the latter takes a lot of self-control which can easily crumble when the right buttons (sometimes unknowingly) get pushed. One way to control this is to minimize all externalities which could trigger an emotional response eg. it is easier to have a rational conversation via simple text (various modes) vs. face-to-face where tonal/non-verbal cues can trigger unwarranted emotional responses derailing from the subject at hand; Biology, Psychology, Operant Conditioning etc. are all relevant here.
Emotions/Feelings are fundamental to existence itself i.e. they are the drivers for everything else. There is a lot of fascinating research/understanding going on in this domain which is worth studying. You might find the following two books interesting;
1) The Emotional Brain: The Mysterious Underpinnings of Emotional Life by Joseph Ledoux.
2) How Emotions Are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
See also The Rationality Paradox: Balancing Logic and Emotion - https://fastercapital.com/content/The-Rationality-Paradox--B...