proper tea etiquette - http://www.straightdope.com/mailbag/m971211b.html

Regarding the mailbag article on proper tea etiquette (http://www.straightdope.com/mailbag/m971211b.html): I’ve never heard the “cracking tea cup” theory before but there actually is a rather good reason for putting the milk in first - it keeps the milk from scalding. Here is why: When you put the milk in after the tea, the small body of milk in the cub is immediatly assaulted by a deluge of boiling hot tea with the result being that the milk scalds. When one puts the milk in the cup first, however, the situation is different. Now, the milk has time to warm more slowly as the first pour of tea hits the comparatively larger body of cold milk. Next time, consult an Englishman rather than “Joy of Cooking”.