Sean Ellis Test (40% very disappointed)

Biological Parallel

The 40% threshold mirrors critical mass in collective behavior: when 40% of a fish school commits to a direction, the entire school follows. Below this quorum threshold, the group remains indecisive and fragmented. Similarly, when 40% of Dictyostelium slime mold cells signal 'very disappointed' (via cAMP), the colony aggregates into a unified organism. This threshold isn't arbitrary—it represents the tipping point where individual preferences create collective lock-in. Product-market fit occurs when enough users would be 'very disappointed' to create irreversible adoption momentum.