When I was 10 years old we moved from California to El Paso, Texas. On my first day in school there the teacher asked me a question and I answered, "yeah." She very quietly said, "When you speak to me you say, "yes, Ma'am."
That is why I was so surprised to hear some of the terms (bucks, guys) used by Chip and Joanna. Maybe things have changed, or they didn't grow up in Texas. Or it could be producer driven to add folksieness, which is just wrong.