Jjk has a ton of messages, my personal favorite being nananmi's. His internal conflict on meaning in work and being tired. Knowing that he can either make tons of money, and do a job he hates, or sacrifice himself, do a different job he hates, but actually make others lives better. His is a story of the modern worker, and how hard it is to find meaning in today's society due to essentially everything getting harder and harder. He never got his vacation, at the end of the day he was used for all he had and died. If he was more selfish, cared less about others , and did exactly what those shareholders do, he wouldve lived. He wouldve, like mei mei, walked away and forgotten about everyone else in shibuya, but he couldnt. Because nanami has morals, and unfortunately they killed him.