Our gym TV automatically close captions whatever show you're watching. There's no remote control, and no way to turn this function off (the buttons on the TV consist of volume up/down, channel up/down, and power). It's fun to watch America's Next Top Model this way, and see how people really talk (I don't include "smizing," and "Ty-overs"), laid out for you on the screen.
People are repetitive, nonsensical, and prone to "um, like, totally" when they speak (I'm especially bad with "like"). If I transferred what people actually say into a book, it would be both annoying and boring, albeit with occasional sparks of brilliance. So then here is the dilemma: is it better to be realistic or clever with one's dialogue in a novel? Is it possible to be both?
"Cleverness" is subjective, of course, and can run the risk of pulling readers out of a story, if they're distracted by the thought "No one really talks like that." I love the dialogue in old Bogart movies, particularly "In a Lonely Place," and "Casablanca." But I also love when dialogue rings so true it hurts.