Yes, Sanctus, I recognise where you're coming from.
I went through a phase where I preferred not to say good morning/good day/good evening/good night to anyone. To a lesser extent, I also had trouble with 'thank you', 'you're welcome', and other little formalities.
I believe the reason why I was reluctant to say these phrases, was that my mind didn't see any immediate cause for uttering them from a purely objective POV. They're mainly phrases designed to 'smooth out' a conversation, but they don't serve to purely convey information, which is why I found them redundant.
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clarity of thought before rashness of action