Dean: Dad never treated us like that!
Sam: Well Dad never treated you like that, you were perfect. He was all over my case. You don't remember.
Dean: Well maybe he had to raise his voice, but sometimes you were outta' line!
http://community.livejournal.com/spnquotefic/3449.html?thread=261753 - t261753 Dad didn’t yell all that much. He didn’t have to really. He could throw a kid a stare that could melt steel. Sometimes all he did was give a disapproving look, which for Sam, was almost worse than the laser beam of death look. Sam could barely admit it to himself, but he wanted his father’s approval almost as much as Dean. Wanting and getting are two different things though.
Sam remembered the first time he went toe to toe with Dad. He couldn’t remember why it happened, only that it had. His father had raised his voice and something had gone white in Sam. It turns out that Sam didn’t see red when he was mad, he saw was white. Everything all fuzzy and pale on the edges and suddenly Sam was up on his feet, yelling at his father, his voice cracking with stress and hormones. It was rather impressive actually, even Dad had seemed shocked. Not so much that Sam had disagreed with whatever Dad wanted, more that Sam had the balls to step up to the old man and confront him with it. Dad had never liked his sons’ questioning him but out right disrespect was horse of a different color.
Sam knew that yelling Dad was scary, but then Dad had dropped his voice to a low growl, pitched to a rumble that carried across the small apartment and suddenly Sam realized that quiet Dad might be worse.