It was my first house, we had moved across the country and were not present during the home inspection. To make things worse, I didn't READ the home inspectors report describing the shut off locations. After ripping up carpets and painting, my wife suggested changing out the bathroom faucets. I said that should not be a problem since I have completed many DIY projects in the past. When I removed the bathtub faucet in the second floor bathroom, water started shooting from the open pipe into the back of the tub. That's when I realized something even more horrifying, I did not know where the water shut off valve was. Was it at the street? Maybe in the basement? In my haste, I shut off the water and the gas in the basement. It was fortunate we had a home warranty. We paid the service call fee for the technician to come out and turn on the gas and light the furnace and water heater. While he was there, he pointed out the location of the gas and water shut off valves. It was a lesson learned the hard way.
Know where your shut off locations are before you need them. It's a terrible feeling trying to find them in a panic.