(CNN) -- Of the eight "Harry Potter" movies Daniel Radcliffe made, there's one in particular that sets his teeth on edge.
The 25-year-old actor, who portrayed J.K. Rowling's adolescent wizard hero for 10 years starting at age 11, admits to the Daily Mail that it pains him to watch 2009's "Harry Potter and the Half-Blood Prince."
"I'm just not very good in it," Radcliffe bluntly told the UK publication. "I hate it. My acting is very one-note and I can see I got complacent, and what I was trying to do just didn't come across."
It's not that Radcliffe is ungrateful for the experience. On the contrary, he calls the opportunity to play the globally adored character "an incredible blessing, because it gave me this opportunity to start a fantastic career."
But Radcliffe was still getting started as an actor when he was cast in 2001's first "Potter" film, meaning the franchise also holds "the moments I'm not as proud of," Radcliffe said. "Mistakes other actors get to make in rehearsal rooms or at drama school are all on film for everyone to see."
Though admittedly self-critical, there is one "Potter" flick that Radcliffe is happy with: "My best film is the fifth one," he tells the Daily Mail of 2007's "Order of the Phoenix," "because I can see a progression."
As he's taken on more complex and varied roles in an effort to leave Potter behind, Radcliffe has become more confident in his talent. In August, he stars in the romantic dramedy "What If," playing a character that's "someone most like myself," he told the Daily Mail.
"I'm definitely the geeky guy who wants to be in a relationship," he said. "And it was a big thing for me to do a modern-day romance. There was no point in this film where I had to get covered in blood or cry over the body of someone or pull someone out of a muddy bog."