Hiking is just walking where it's okay to pee.

Martin’s line reduces the lofty, outdoorsy romance of “hiking” to a blunt practical distinction: social permission. The humor comes from deflating a marketed, identity-laden activity into ordinary walking plus a change in etiquette about bodily needs. It also pokes at how people use labels to make the mundane feel adventurous or virtuous—“hiking” as a rebrand of walking that signals ruggedness, nature, and escape from urban rules. By centering an unglamorous reality (peeing), the joke highlights the gap between aspirational narratives of outdoor recreation and the basic human logistics that actually shape the experience.