BEFORE: Rodney McKay
Before Atlantis, he was Mer to his little sister, Jeanie, Meredith to his mother (Merry, when his mother was in a rare good mood), and simply Boy when his father chose to acknowledge his existence. Now he's Doctor McKay to his staff, McKay to his team (and Rodney on occasion), and still Mer to Jeanie, although it doesn't really bother him as much as he claims.
Before Atlantis, a hand raised in his direction usually meant a blow would follow. A slap from Jeanie for teasing her too much, a punch from one of the kids at school for being smarter, a different sort of slap when his mother was tired of his "attitude," or (most painful of all) a dismissive wave from his father. Now a raised hand means a greeting - hello, how are you, come over here. It's a clap on the back when Sheppard is pleased. It's a one-armed hug when Ronon catches him. It's the tiny, defiant fist of Teyla's son.
Before Atlantis, he was arrogant, pushy, annoying, fretful, cowardly, introverted, awkward, and alone. Now... Well. He's not alone, at least.
