If the long-form nature of TV drama can take viewers on an epic journey with an ensemble of characters who evolve over the course of its run, sometimes this happens in ways audiences could've never quite seen coming.
A new TV show fronted by an out-and-out villain protagonist can be a tough sell, so it's decidedly more common for showrunners to introduce viewers to good-hearted or more ambiguous figures who, as the seasons wear on, become increasingly contemptible.
That's certainly the case with these 10 hit TV series, which initially left audiences sympathetic to their protagonists, but of course, life inevitably has other plans as it so often does.
By the time these characters left our screens, viewers had witnessed an unexpected slow-motion heel turn, forcing everyone to consider how they felt about spending several years clinging to every word of - and possibly even rooting for - such an ultimately detestable character.
In many ways that was exactly the conversation the creators wanted to spark among viewers, while in others they perhaps didn't realise quite how loathsome their apparent anti-hero protagonists had become...
10. Game Of Thrones
Game of Thrones is an especially interesting case to consider, given that the main reason audiences were surprised at Daenerys Targaryen's (Emilia Clarke) final season heel-turn is that the poor writing made it feel so sudden and contrived.
Dany's arc over the course of the show saw her transformed from victim to fierce protector of the downtrodden with the eventual goal of claiming the Iron Throne.
She certainly wasn't afraid to take the lives of those who had wronged her or others, though Dany became decidedly less sympathetic in season eight when she underwent a hugely unpopular personality transplant.
After living through the deaths of Missandei (Nathalie Emmanuel) and her dragon Rhaegal, and also learning that Jon Snow (Kit Harrington) had a stronger claim to the Throne than her, Dany quickly descended into murderous madness, torching King's Landing and most of the audience's sympathy for her along with it.
Despite many expecting that Dany might "win" Game of Thrones just a season earlier, by the end of season eight it was a simple inevitability that she had to be put down by Jon.
Unsurprisingly, many fans were left baffled by this apparently "destined" fate for Dany, given that the prior seven seasons seemed to be laying out an entirely different fate for her entirely. A shocking heel turn if there ever was one, for sure.