This story was told to me by a plumber I know and it brings home the reason why there are times to call a professional.
I received a call from a homeowner asking for someone to come estimate some repairs. When I asked the sort of repairs, he said it would be too many to enumerate, but much easier if I just came out to the house and looked. I went. It began like this …
Old Joe wanted to change his toilet seat, but could not get the old one off. So he tried wrenches until he rounded off the nuts (he was turning them the wrong way because they were upside down) and then decided to get his trusty cold chisel and hammer out. Well, he tapped a bit on it with no success, so he drew back the hammer to smite a mighty blow against the stubborn bolt. In so doing he broke the toilet tank and flooded the area with cold water. This cold water gave him a shock and he drew back in a hurry dropping the hammer into the bathtub causing a big chunk of the porcelain to pop off the tub floor.
Regrouping his thoughts, he ran down to the basement two floors below to shut off the water to the house, the house had no other valves installed when it was built in the 1890's. Meanwhile water was flooding through the floors and had saturated the plaster of the ceiling below to the point it collapsed into the living room. Old Joe then removed what was left of the toilet tank, and tried to remove the bowl from the floor flange. It would not budge either, so out comes the trusty chisel and hammer again, and "WHACK" no more toilet bowl. In the process however, he managed to tear the closet flange from the floor as well, and since it was attached to a lead closet bend, it torn and now needed replaced too. He determined that it would be necessary to cut out the tee in the stack where the closet bent was attached. Since he had no idea how to repair old lead piping, he thought using that nifty PVC from Home Depot would do the trick.
He tried to cut the cast iron stack with a hacksaw to no avail, then tried a sawzall, also fruitless, so …. yep, out comes the good old chisel and hammer, but a bigger hammer this time. He whacks on the stack a few mighty blows and Viola 'it splits into several pieces with one tiny segment still holding it all together. He pried the last vestige of solid pipe out of the wall with a crowbar and suddenly the remaining section of pipe (the vent going through the roof) lets go and with a mighty crash comes down and out of the wall through the sub floor into the now plaster less ceiling of the living room, continues its downward decent until it hits the TV set, ricocheting off that and through the floor of the living room until it hit the electrical panel plunging the house into total darkness and finally comes to rest after shearing off the main water shut off valve flooding the basement.
This was a $ 27,000 toilet seat replacement.