growing up, not only did you have to be at the table at 6pm sharp, but clean and properly dressed (no sleeveless shirts, anyway). it was probably the only rule in our house.
dw and i have almost always eaten together, unless i'm working really late, like past 9pm. we also wait for each other to start if one of us is delayed or interrupted. sometimes, you could be hurtin for food, with a big hot plate ready to be inhaled, but we always wait until whatever interrupted one of us is dealt with.