Humor is the tendency of a cognitive experience to evoke amusement, often accompanied by laughter. Most definitions of humor state that it serves as a means to uplift one's mood and establish commonality between individuals.
Every known sentient species and culture possesses at least some sense of humor, and there are many different interpretations of humor as per cultural and personal taste. Certain societies may prefer humor that reflects upon or imitates real life, while others prefer paradoxes, reframing, hyperbole, puns, metaphors, etc.
Most planets have a great diversity of humor to go along with cultural diversity. However, a planet doesn't need to be monocultural in order to have a predominant preference for a certain type of humor. Planets that are ill-kept and have an overall deficit in morals, such as Riesel, tend to prize audacious and vulgar humor over other forms. Conversely, planets known for cleanliness and prestige tend to have a higher instance of more refined humor.