I was standing in the kitchen when she pulled the plug upstairs. Suddenly, the sink started making these noises like a cheap horror movie. Except I didn't see a poltergeist when I looked in. Instead I saw the entire contents of the bathtub coming up to greet me. I wish I had seen a ghost or evil spirit.
Priests are easier to find and far more reliable than plumbers.
A few bottles of highly toxic drain cleaner later things were moving along very nicely. Mostly up the drain in the basement and all over the new wall to wall carpeting. That's when I knew I was in over my head - or would be soon if the stuff kept bubbling up through the floor. We've been lucky. Seven years in the same house and no plumbing complaints, except for a toilet handle you have to jiggle and kitchen taps put on backwards.