Saturday's New York Times has an interview with Richard Anderson, CEO of Delta Airlines, on his leadership approach. I liked his answer to what his most important leadership lesson was, "I've learned to be patient and not lose my temper. And the reason that’s important is everything you do is an example ... when you lose your temper, it really squelches debate and sends the wrong signal about how you want your organization to run."
I have to agree. If as a leader you really want to squelch debate, just come out and squelch it. "Okay, that's enough debate" can work just fine. There is no need to kill ideas accidentally.
The interview is worth a read.