(CNN) At the risk of being booted from the TV critics cool kids' table, "The Leftovers" has always felt a trifle overrated -- an intriguing premise that became too enamored with its own eccentricity.

In that regard, the HBO show -- which returns for its third and final season beginning April 16 -- has become emblematic of a subgenre that has gained a growing toehold, one that New York Times critic James Poniewozik recently dubbed "surreality TV." The basic formula is a program that dares to be impenetrable for many, while presenting an enigmatic mystery, complete with a trail of bread crumbs, designed to dazzle the few, including the critical establishment.

"Leftovers" has gained a fair amount of company in fitting that description. Other examples include the FX series "Legion," the second season of USA's "Mr. Robot" and Starz's upcoming adaptation of Neil Gaiman's novel "American Gods." "Twin Peaks," an ahead-of-its-time exercise in surreality, will also be revived on Showtime in May.

Some of the shared traits include complicated flights of fancy, occasionally blurring the lines between fact and fantasy; and doling out story in measured drips, advancing the plot at what often feels like a snail's pace.

Television writers have clearly embraced this expanded freedom, and prestige networks have grown more willing to indulge them. After years of TV that operated within relatively rigid and narrow creative parameters, there's a certain thrill in seeing writers flex their storytelling muscles, even when the results can be a tad confounding.

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