CGP Grey looks at why hexagons are so great, and why honeybees like them so much. It comes down to tiling efficiency. Unlike triangles and squares, hexagons do not divide into smaller versions of themselves, meaning they are very efficient for making sturdy walled containers with minimal material.
My own interest in hexagons is related to visual hallucinations, specifically the architecture of the human visual cortex and how inhibition and excitation of neural activity leads to the tunnels, spirals, honeycombs, and cobwebs many people experience under the influence of certain hallucinogens.
Image: YouTube / CGP Grey