Socials are commands used to express emotions in pre-scripted ways. There are three general variables to socials: No argument, self, and other. There are also differing viewpoints: What you see, what your target (if any) sees, and what others in the room see.
Many of TFC's socials were written by players. For information on creating a new social, please read Social Writing, and submit the idea in the Ideas section of the TFC Forum.