In other words, the character that you can relate to or has similar personality traits to your own.

About 50% I would say my favorite is the one I can relate to or see a lot of me in them.

Examples from my experiences with anime:

Soul Eater
Most Relatable: Tsubaki
Favorite: Tsubaki

Ghost Hunt
Most Relatable: Naru
Favorite: Naru

Puella Magi Madoka Magica
Most Relatable: Homura
Favorite: Homura

Hetalia
Most Relatable: Japan
Favorite: Japan

Amnesia
Most Relatable: Shin
Favorite: Shin

Sorta. Some are relateable and some are types I try and emulate but fail miserably.

Opposite really :) I admire/adore characters who I know I could never be -the valiant, selfless, charismatic, strong, apathetic, humorous, loud, etc
I realized this when I thought of characters like Kamina (Gurren Lagann), Revy (Black Lagoon), Sasha (Attack on Titan) etc XD

tbh, I never found a character whose personality reflects mine.

@Aisuanime Haha, I like a lot of characters like that as well because of how shy and non-outgoing I am.. x3

Like I said, I always try to find something similar with all my favorite characters.

@dianeyoung Same for me.

I usually like killers so...

I believe that this can be natural, given that having such similarities with a character will make you feel a strong connection with them; therefore, strongly liking them, but it isn't always true. There is a character, Mello from Death Note, who I always feel that I understand so much, but we aren't alike, at all. Here is a list of my own..

Death Note
Most Reflected Character: I have come to realize that Light Yagami's personality reflects mine, the most. Despite the fact that we have 100% opposite moral views, there are other reasons that I do not feel like explaining.
Favorite Character: L

Black Cat
Most Reflected Character: Eve
Favorite Character: Sven

Clannad
Most Reflected Character: Tomoya
Favorite Character: Tomoya

Air
Most Reflected Character: Yukito
Favorite Character: Yukito

Some characters reflect me but some are just plain psychotic XDD

^ Most of the characters that I act like have a few screws loose so I get what you mean there. X)

Most of my favorite characters reflect more of what I wish I could be. ^ ^
And some are just extremely interesting but are insanely nothing like me or what I wish to be like. XD

^ I see. :) I have the same thing going on with my list as well. x3

Most of them are characters that I want to be like, or characters that I just really love the awesome personality of. Sometimes my favorite relates to me though. (:

^ Yeah, that makes sense. I also have that thing kind of going on with my favorites so I see what you mean. :)

The majority of the time my favorite character's personalities are like the opposite of mine...

It actually depends. ~

Sometimes that's the case, since I can relate to them a lot.

But then I admire characters greatly for being able to do things that I can't.

So 50 50 for me. =)

^ I agree. :) Nice answer. ^ ^

Sometimes they are. But its 50/50, since I also really like characters that are opposite to me, or ones that I just find interesting.

^ Understandable. I do the same thing as for me, I also like characters that can do things that I am not capable of doing with a personality like mine so yeah. I see where you are coming from though, :)

nah because i don't think i'm evil and angry deadbeat dad that destroys planets

Yupp!

I am a harsh person who always speaks my mind and always ends up hurting people. While on the inside I am nothing like that, and I really just want to help people and be a good friend.

If there is a tsundere chara in a series they are usually bound to be my favorites. I don't know why. Since i'm no that into myself I don't see why I always like them the most.

Maybe I just want to see them succeed with the hopes that I might someday?? (Not that i'm depressed and fail at everything, my confidence is just horrible! Even If i'm VERY good at hiding that))

But mainly because I never really thought about it :/

For the most part, that is not true for me, but that is probably because I hardly find characters to whom I can really, really relate to. However, there have been cases where I did find those characters whose personalities matched mine almost to a T, but only a few of them were my favorite character of their respective series, in actuality.