Jack O'Neill shaving.
Shaving is an act where male or female Humans can remove their facial (mustache, stubble) or other body hair. They can be performed by two methods. One is where one applies foam on their cheeks and chin, and use a blade to shave. The other involves using electronic razors.
In 2004, Colonel Jack O'Neill was shaving while solving a crossword puzzle. (SG1: "Lost City, Part 1")
On board Destiny, Lt. Matthew Scott and Colonel Everett Young use both methods. (SGU: "Space")
People can also wish to shave off head hair. Teal'c would often shave his head until 2004. In 1999, when Teal'c and O'Neill swapped bodies, Teal'c in O'Neill's body wished to shave his head, much to the behest of O'Neill, who wished Teal'c to hold off until they can return in their own bodies. (SG1: "Holiday")
In 2009, Mess cook Pvt. Darren Becker found a new duty in shaving the heads of military personnel, including MSgt. Ronald Greer. (SGU: "Sabotage")