He told the Daily Mail:
It’s hard to watch a film like Harry Potter and the Half-Blood Prince because I’m just not very good in it.
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.
And he pointed out millions got to see him develop as an actor as he grew up in front of the world.
The moments I’m not as proud of, mistakes other actors get to make in rehearsal rooms or at drama school, are all on film for everyone to see.