" So what’s the rule of thumb? Some say you should always match your socks to your shoes. Others say you should always match your socks to your pants. The correct answer is pants. And so in the case of jeans and brown shoes, I would go with navy socks.
One note on sock-and-pant etiquette: if you’re wearing socks with dress pants, you should reveal no leg skin. It’s like a bare midriff: you don’t want to see it. It’s different if you’re wearing shoes without socks, which is fine in casual settings. "

― , Tim Gunn's Fashion Bible: The Fascinating History of Everything in Your Closet