Notability is important for preventing a potentially slippery slope towards Wikipedia being expected to have an article on every shop, every street, every apartment complex, every popular teacher, and every creative work ever appreciated by more than 10 people.
However, there is something frankly awful about the way it is handled.
Deleting an article should be a grim and thankless task, carried out in the stoical way that a county bailiff would hang or brand a petty thief. Instead, it seems to be a matter of great pride and satisfaction to those who elect themselves to carry it out. These folks really seem to enjoy making up pedantic excuses to remove things, even when faced with strong opposition and enough evidence to at least raise reasonable doubt. When I have checked many of these editor's commit logs, I frequently find that they do little else but marking other articles for deletion, adding "citation needed" after junior highschool level facts and giving barnstars to other like minded nimrods.
If one has contributed in good faith to an article that has been marked for deletion or even appreciated reading one of these articles, it is hard to maintain one's passion for the project. Back when I was a regular contributor, I was creating articles for large international airlines and the like. Then when those were all finished, I made ones for well known video games, books, composers, etc. After those were done, there seemed like nothing remaining but the obscure. But at this time, it was so hard to be excited when one needs to justify each time why Wikipedia would not be better off if what you just wrote was erased, So for the last 7 years, I've pretty much just changed a comma or semicolon here and there.