When it comes to falling in love with a character in a book, I am very particular about that character’s words and actions. It’s more than just physical appearances; there are the words an author chooses to put into his or her character’s mouth, his/her interaction with other characters and his/her actions in any particular situation. It might be a little obsessive to think this way, but the adjectives and adverbs used to describe them, or their actions throughout the story, make a huge difference in how I picture the character in my mind.
For instance, a sophisticated and somber personality is unlikely to be doing anything ‘jauntily’, or ‘merrily’ (especially not dialogue), just as a light-hearted interaction would not be conducted ‘fiercely’ or with any kind of melodrama. The debonair hero of a romance novel should not, I believe, be attributed with actions or words that are stuttered or stammered, stumbling or diffident. I would prefer ‘hesitant’, or ‘reluctant’, neither of which bring up images of chastised little boys in front of a stern schoolmaster. Though, I may be wrong about the romantic hero part—it really depends upon the character you’ve created—but a hero who is supposed to be self-assured and commanding loses his charm when he’s responding in a ‘small voice’, or saying something ‘jerkily’.
And it’s not just adverbs and adjectives that this applies to. An older woman may ‘chide’ a child, but it’s unlikely that she’ll be chiding an adult—setting them straight, or remonstrating, perhaps. The quirky young college student won’t be ‘stern’, or ‘somber’, though she may be ‘passionate’ and ‘eccentric’. The octogenarian won’t be ‘skipping’ along the sidewalk, and rarely ‘snarky’ (unless he’s very, very cool).
Just like you’d rarely describe the heights of passion as ‘cheerful’, or the depths of despair as merely ‘sad’, selecting the right word for the right character and the right situation is what writing is all about.