I suppose you could attach this metaphorical hysteria to anything in life that lures you in, never to let you out. It could be drugs, booze, love, a job, depression, religion, etc. By avoiding exposition, Teshigahara let's us attach whatever ails us to the narrative. At the time I saw it, there were three very pressing/oppressive problems holding me down. It reminded me of the things that I need and how I obtained them, and ultimately where they got me. I'm bound to a cycle, now and forever. It's a depressing thought, one that I sometimes try to suppress. This movie hasn't left me as a result.
Do we shovel to survive or survive to shovel. Sounds simplistic. It probably is, but it's heavy to me.