No problem, I don’t mind answering again! :) My favorite character is Yami Yugi/Atem. I’ve gone on about him in words before here and here and probably plenty more during my liveblog, so I guess I won’t do that this time. The short version of why I love him though is because:
A. He’s awesomely overdramatic and badass.
B. He’s really hot.
C. And he’s a super dork.
Of course there are plenty more reasons as well, but those are just a couple. :)
As for least favorite, I’d say it’s a toss-up between Haga/Weevil and Gozaburo Kaiba. They’re both pretty unsympathetic characters who have done really crappy things, and while other Yu-Gi-Oh villains have certainly done crappy things as well there’s usually something about them that mitigates it somewhat and allows you to sympathize with them. Haga has nothing as far as I can see, although I know that there are some who are able to find a reason to enjoy him and that’s fine. For me though, he’s just unrelentingly nasty and a cheater and there’s just nothing interesting enough about him to allow me to possibly overlook those things.
Gozaburo is pretty much the same. He was pretty much a completely crappy adopted father to Seto and Mokuba, especially in the manga from what I understand from what others have said, and he really wasn’t all that much better towards his actual real son in the anime either. Sure he stuck him in a computer and gave him things to try and keep him happy after his body died, but he eventually stopped doing that and pretty much tried to manipulate him during the Noah arc. He’s just a really unpleasant person overall.