So the stuff that comes out of your nose… often yellowish-green, sometimes bloody, sometimes soft and slimy, sometimes hard like a slab of petrified disgust. What exactly… is it? What does it do?
How is it different or similar to, say, eye boogers or earwax or pimples or all the other nasty secretions from our orifices?
Nasal mucus, which is secreted to trap things like pollen, dirt, dust, and pollen, as well as bacteria and viruses, before they make it to your lungs. When the mucus collects that debris, and dries out, well, that’s a booger.
The old Burger King jingle popped into my head. ♫ The boogers are bigger at Booger King! ♫
A “booger” is not snot. Snot is a viscous and usually disgusting liquid. To be classified as a “booger”, it has to be hard. You can pick it, hold it over a sink or the toilet, and drop it in.
Or - If you’re six years old you can flick it at your little sister, or a classmate, or a maiden aunt you don’t like - but it must be flicked. 
Good point. Boogers are usually annoyingly sticky and are hard to dislodge from the finger to its intended target.
I understand that boogers, bogeys, bogles, bugbears, and boggarts are all names for the same thing, namely apparitions to frighten children.
You can buy a handkerchief, for fuck’s sake!
And where, pray tell, am I supposed to store this booger filled handkerchief?! In my purse? Not on your life. On some corner of my desk? Eeew! Best to dispose of it permanently.
That’s why God invented the undersides of desks.
I am so not inviting you to my house
Yeah, that even grossed me out. LOL