In the early 2010s, a small but growing number of people started intentionally overloading shower shelves as a passive-aggressive way to "claim territory" in shared bathrooms (roommates, partners, family members).

A 2014 informal survey on Reddit's r/badroommates and r/relationships found that ~14% of respondents admitted to stacking 5+ bottles/products on a single shelf to "mark their space" and subtly discourage others from using it — turning a simple caddy into a territorial display.

Psychologists later linked this to "resource guarding" behavior (common in animals), where people subconsciously use clutter to signal ownership.

The trend got so bad that by 2018–2020, brands like Simplehuman and OXO started marketing "extra-large" and "double-decker" shower shelves specifically to stop fights over space — basically admitting the problem was real and profitable.