“Hot heads and cold hearts never solved anything.” - Billy Graham
In other words, don't lose your temper and have a heart! Have you ever noticed that people who easily lose their temper also happen to be very insecure. Not always the case, but the majority of times people who lose their temper and are easily set off because they can't stand looking bad. Or, they're so incredibly selfish they have to have things their way or have things falling in their favor at all times. In any event, having a temper flies in the face of servant leadership as the individual is almost always at the center of their decisions and actions.
In some cases being stone cold is probably great. Being cold-hearted eliminates emotion, thus making decisions very black and white. I think cold-hearted decision making in some instances is good (i.e. when evaluating a situation where our Guiding Principles have been violated). But, when it comes to leadership and personnel, our hearts require a prominent seat at the table. People need to know you care, and the only way to care is to show a warm heart. Not easy for some!