The Age of No

Do your children treat you like their maid-servant? I swear mine do. At least the girls, but they're teaching their little brother a few tricks already. When you ask them to do something, do they just tell you, "No," and go right back to what they're doing? Or if not, they throw themselves down as if the world has fallen into pieces around them and they'll never recover from the tragedy of being told it's time to get ready for bed?!
My apologies for the run-on sentence. Perhaps I was not at all meant for motherhood, but it's too late now. They won't be going back where they came from anytime soon. The womb is closed! Therefore, we have to soldier on together. Papa, the 3 children and me.
Apparently around the age of 6, the "No" word comes back (remember that 2-year-old 'no' stage?) as a favorite. Children at this age also work on perfecting the art of ignoring their parents. This is a stage that tries a parent's patience, but it is compounded when there are younger siblings around. Remember when your sweet, little baby modeled you? Now the younger children prefer to model the elder sibling.
I can handle one child ignoring me, telling me no or even throwing a tantrum. What causes the steam to rise in my head until it feels that it may literally burst off and fly off into space is when I have three children defying me. They join forces and suddenly there is "Team No-To-Mommy" in the room.
I despise yelling at my children. But in these moments I don't know what else to do and out comes the shout. When I've regained my cool (and they've done what they were told to out of fear of their crazed, shouting mommy), I have shouters remorse. Then I wonder if I'm the worst mom in the world. Then I agree to shirk all of my duties and have coffee with my friend (who has two daughters exactly the same ages as mine). Then I feel better.
How do you handle being told "no" by your children? What discipline do you enforce? Tell me about it or feel free to link to your best post about it!