I didn't understand before, why do some adults, whenever they receive a call from their boss, even while taking a shower, quickly dry their hands, clear their throat, and answer respectfully.

It wasn't until I started working myself that one time I was sleeping, and my boss suddenly called with a video call. I panicked and answered. That flattering smile on my face, I was even surprised myself.
Later, I checked the call records and found that no one had ever taught me that smile; it grew naturally from within myself.