Lots of jobs look different in movies than they really are. My uncle thought fishing was all adventure, but it's mostly early mornings and hard work. At your BBQ, maybe share a quick story about the boring parts of diving, like equipment checks. It can fix the idea without ruining the fun.
Totally get that. When friends think my work is all creative sparks, I'll mention the hours spent on client revisions. Kinda like equipment checks, it grounds the fun stuff in real work.