Something Idiotic That Almost Everyone Does

I've recently noticed that a lot of people, when waiting for water from a faucet to become warm, will turn the water on so that when it is up to temperature it will be the temperature that they want. When you do this, some of the water comes from the cold water line. This water is completely wasted. Also, since you're not pulling the maximum amount from the hot water line it is going to take longer to empty that line of room temperature water.

I'm not much of an environmentalist so I'm the last person that would be telling people to conserve water. I am, however, interested in making my life more efficient. So, when you want warm water turn it fully to the hot side until it warms up then adjust it. Water conservation is just a nice side-effect.