EDIT: for clarification: There is only so much space between the front of my head and my brain. How does so much snot fit in there? Is it generated continuously so that there is always more available? Does it come from the lungs, and if so, what is the process of transport to my nose?
One thing it took me SO LONG to figure out is us normies call the whole thing “sinuses” but to the science hippies, the sinuses and the nasal cavity are different things. All of which can be clogged with mucus that regenerates.