Meredith was always the one to be placid, even in the most frightening moments. She hardly ever loses her cool--not on the outside, anyway. And her bravery is infinite.
She has this bright flame that is her soul, and it burns with a passion. She also has a unique way of latching onto the Supernatural world, aquiescently taking in the weirdest of things, yet still holding a firm grip on logic. With that fire living inside of her, it's hard to mistrust her.
You would never find anyone holding her in a half nelson; actually, it would probably be the other way around.
Meredith isn't one to loiter when trouble looms near. And she's brisk to stand up for what she believes in, whether it's friends or opinion. Her heart is large and open, but never barren.
Oh... One other thing: she has a great sense of fashion; she's always presentable, usually dressed for the occasion and with style.