Shinichi comes to mind.
Yes, I'm serious.
For the most part, Shinichi can be so arrogant and annoying. I'm beyond glad that he has to live as Edogawa Conan because it teaches him to be humble. Even though I hate it when Kogoro throws him out the room, Sonoko makes fun of him, Genta calls him his apprentice and the Detective Boys take credit for everything he does, after seeing the first episode a few times, it's quite clear to me that Shinichi needs to be put in his place. Now, even though he's pretty awesome the few times he does reappear as Shinichi, that's just because he's learning not to take everything for granted. You can see this easily when, even though Shinichi is said to have been a show-off more than once, the first time he turns back, he tells Hattori that it doesn't matter who the better detective is and that finding the truth is all that matters. This shows that he's actually learning something as Conan. Also, there's simply the fact that Conan handles everything from Shinichi's character, especially his arrogance and negative qualities, better. I mean, all the snide comments look adorable coming from Conan and yet, from Shinichi, they just seem immature.
I honestly wish that Shinichi has to stay as Conan forever, lest his arrogance as the renowned high school detective return.
Oh, boy, I just declared my hate for the most popular character in the series. *puts up shield*