Say what you want about BBC Merlin, but none of the actors had to go as hard as they did with their performances. It was a show for kids, the CGI was shite, and on Robin Hood (which was the series before Merlin) no one except Richard Armitage bothered to act as seriously.
But the fact that they did is what makes it so popular, what makes it endure, what pushes it and its characters and ships up the list in the fandom metrics each year. The actors took it seriously, they left an amazing legacy, particularly Colin Morgan and Bradley James. Even the devastation of the ending couldn’t break the fandom apart because it was sad, but it was so well done you almost didn’t mind. And that’s why a show which ended eight years ago is still so strong in the hearts of so many people.
Merlin + never quite believing that Arthur can get dressed by himself.
+ Bonus. Arthur the other 99% of the time: