The fourth wall break is a staple of postmodernist pop-culture. Everyone's seen some example of a 'pop-conscious' piece of entertainment, a movie, TV show or book that exists to remind you that's exactly what is, a piece of media that's in conversation with itself.
It can be a fun reminder of the existence of the author, and the process of creating the art being appreciated. Or used more broadly, it can be a device to deconstruct the form itself; a story about stories being written, in the case of Charlie Kaufman's Adaptation or Synecdoche, New York.
But a true fourth wall break, where a character acknowledges their own existence as a fictional character, can in the right circumstances be charming, and in the wrong circumstances be jarring.
Let's take a look at some of characters who really wanted you to know that yeah, this is a movie.
The character who took the idea of breaking the fourth wall as his entire raison d'etre. Beginning in the comics, Deadpool would often speak directly to the reader, comment on the story from the inside, and generally live one dimension higher than his other Marvel brethren.
Naturally this continued into his solo film, with the movie's opening credits even referencing the trite and unimaginative casting superhero films usually utilise. Unfortunately the movie forgets to transcend its own critiques, not offering up any better ideas than the ones it's lambasting.
The more memorable moments of self-awareness in the movie include Deadpool commenting on the also-ran level of X-Men the studio is able to afford on his Xavier Mansion visit, and asking which Xavier (McAvoy or Stewart) Colossus is taking him to.
He also references another fourth wall break on this list, appearing at the end of the movie wearing a Ferris Bueller-style dressing gown, and telling the audience what to expect in the sequel, before delivering the exact same lines Bueller did the first time around.