This is a trope that doesn't appear much in fiction, being pretty much exclusive to {{Fandom}}. The basic idea is that the more seriously a character acts, or the more seriously a story takes itself, the more mature it is.

For example, if a PluckyComicRelief character has a LetsGetDangerous moment and spends a good portion of an episode, film, or book being deadly serious, odds are someone will hail this as the character "finally maturing." And when PluckyComicRelief guy inevitably goes ''back'' to making lots of jokes, someone will complain that the writers are regressing the character. While rarely said outright, the implied idea behind this is that having a sense of humor is a sign of immaturity, and that a mature character will act with grim seriousness at all times. "ThisIsReality" will often be invoked.

This same attitude can apply to stories as a whole, with comedies [[ComedyGhetto frequently seen as being less mature works]] than their dramatic counterparts, even if the comedy ''also'' has some dramatic moments.

Related to TrueArtIsAngsty and ComedyGhetto. A leading cause of DarkerAndEdgier. Fans of this mindset generally want their show to be on the 'Serious' side of the SlidingScaleOfSillinessVersusSeriousness all the time, regardless of whether or not it's appropriate, and are often found saying "SillyRabbitIdealismIsForKids".

On the other hand, overplaying this may lead to denunciation as being a [[EmoTeen mopey adolescent]] or complaints of {{Wangst}}.

A common subversion of the trope is to play it so straight that the characters come off as ComicallySerious; the inappropriate or incongruous seriousness becomes laughable in its own right.