In the shower staring upwards at 7 AM I realized the bell-shaped beauty of my simple shower spigot. The stainless steel nozzle caps the metal pipe emerging from the wall and sprays that water through a hundred tiny holes while I drift in and out of consciousness each morning.
The OED helps us understand that the word "nozzle" has existed in its present primary meaning, "a spout [...] through which a jet of gas or liquid may issue or be discharged," since 1683. That same decade, nozzle also became slang for "nose." The first meaning, archaic now but the only meaning for over 200 years, was "a socket [...] into which [...] a candle is inserted."
After my half-dreamed moment when I no longer took my shower nozzle for granted, I spent the day considering how often I use nozzles. All water I receive comes through a nozzles at the sink or on the office water cooler. Gasoline's pumped through nozzles. Modern living requires the ability to control the flow of liquid, through valves and nozzles.
Nozzles also have an unavoidable phallic connotation. Nozzles cap piping, and are the vessels through which liquid is released. Urbandictionary.com provides an overabundance of obscure slang that plays on "nozzle" meaning "nose" and/or "penis." The imagery deepens: the OED tells us that nozzle operators can be called "nozzle men."
Sources
http://dictionary.oed.com
http://www.urbandictionary.com