I would not unduly praise the virtue of restraint. It is often merely temperamental. But it is not always a sign of coldness. It may be pride. There can be nothing more humiliating than to see the shaft of one's emotion miss the mark of either laughter or tears. Nothing more humiliating! And this for the reason that should the mark be missed, should the open display of emotion fail to move, then it must perish unavoidably in disgust or contempt.
The bottom line is, when people are crystal clear about the most important priorities of the organization and team they work with and prioritized their work around those top priorities, not only are they many times more productive, they discover they have the time they need to have a whole life.