Proof-of-Work
Shower thoughts: Good, tangible and durable assets (knowledge, health, wealth, relationships) come from diligent, disciplined work.
The comparison of smart work vs hard work is too simplistic - it assumes that hard work is menial and repetitive.
More often than not, success comes from putting in the hours, having a plan and challenging yourself.
The outcome, proof-of-work, then reflects the qualities of the actor - it is long-lasting, with integrity and irreproducible.