Thermal Observations on the Preparation of Hot Leaf Juice

I like tea, and I like the British way of making tea, as described by such experts as George Orwell, Douglas Adams, and my spouse. An important part of this process is steeping the tea in a pre-warmed mug or pot. When I can, I fill a mug with boiling water, wait for it to heat up, pour off the water, promptly fill it again with a fresh pour of boiling water, and only then add the teabag.