Sana-chan is the 11-year-old embodiment of a sugar high. She's grown up with a very caring and non-restrictive family, so she's usually in a good mood and never feels the need to repress her hyper personality. Her life revolves around her career as an actress and, like most kids her age, her school, family, and friends.
From a general description it would be easy to assume that Sana is a fairly generic (and maybe shallow) character. Wondering why she's just the opposite, I've come to the conclusion that what makes her so special and endearing is the fact that she is a very genuine child (well, a very-high-on-sugar child). Unlike some other characters, Sana doesn't just look like a child, she experiences and reacts to her world the way a kid would, and she's easy to understand because we've all thought like her at some point.
What I like most about the way Sana is presented as a character is that you can see that she is unpretentious and kind without her creators constantly saying to you in one way or another, "look at how sweet and innocent my character is." In fact, Sana is most often seen loudly rapping to her nori-nori machine, running towards innocent bystanders at 100mph with a demented look on her face, and talking/acting without thinking first.
Sana has an unlimited amount of energy, and I'd say she functions on impulse about 85% of the time (well… probably more). Her mind's always going at full speed, so when she tries to communicate what's on her mind, sometimes she has no time to filter her thoughts so they make sense to her listeners (or herself ^^;). She's also honest to a fault, so if she has good reason to think you're an incredible idiot and need to know it for the greater good, she'll tell you to your face no matter who you are ("oyakodon baka!").
But for all her hyperactivity and rashness, Sana's character has a depth that's hard to imagine from watching the first few episodes of Kodocha. She probably doesn't realize it, but when it really counts, she's able to see beyond people's actions and words to find their cause. Sana is extremely empathic, and that gives her a surprising amount of wisdom about human nature. Because she understands people, she has a lot of faith in their good nature and truly wishes for them to be happy. And although she can be quick to judge out of frustration, she tends to make an effort to give people a chance.
That is probably why she's able to be such good friends with the impenetrable Hayama. Although she does judge him at the beginning, she knows there must be a reason for the way he acts, so she puts all her energy (and that's a lot of energy) into understanding and helping him.
Although Sana never hides her feelings of anger or happiness, she tends to cover up any sadness or apprehension she might feel. Many times she does this because she doesn't want to worry others with her problems, and also because people expect her to always be happy. But thanks to her friends (especially Hayama and Naozumi), she begins to learn to let her guard down in that respect as Kodocha progresses.
Sana's pretty hard to describe in a nutshell, but to me the most basic aspect of her personality is that she is very genuine. She is who she is and never tries to change herself or pretend to be something else. She also lacks any kind of pretense and accepts people for who they are, so she's great to be around (if you can survive all the Komawari Kicks™).
