Water is the most interesting and fascinating molecule in my opinion. Isaac Asimov's essays on water's "strange" properties in his excellent book

https://en.wikipedia.org/wiki/The_Left_Hand_of_the_Electron

opened my eyes to the life enabling properties of this small ubiquitous molecule. Just recently when I stood at a coast watching the waves come and go I imagined all these small molecules bonded together by their electrical bonds.