We're socialized to believe that warmth and strictness are opposites: if you're more of one, it means being less of the other. I don't know where this false conception comes from, but if you choose to believe in it, it will undercut your teaching. The fact is that the degree to which you are warm has no bearing on the degree to which you are strict, and vice versa. Just as you can be neither warm nor strict (you may teach the children of parents who are this way and see for yourself the cost), you can also be warm and strict. In fact, as this Warm/Strict technique shows, you must be both: caring, funny, warm, concerned, and nurturing -- and also strict, by the book, relentless, and sometimes inflexible. It's not, "I care about you, but you still must serve the consequence for being late," but, "Because I care about you, you must serve the consequence for being late."Doug Lemov is describing the approach used by authoritative parents, whose children fare better academically and socially than those of permissive, authoritarian, and neglectful parents.
...Not only should you seek to be both: you should often seek to be both at exactly the same time. When you are clear, consistent, firm, and unrelenting and at the same time positive, enthusiastic, caring, and thoughtful, you start to send the message to students that having high expectations is part of caring for and respecting someone. This is a very powerful message.
A good teacher is like a good parent.