Managers in all spheres of work need to be intelligent enough, for they have technical material to absorb, complex problems to solve and difficult decision to make. But, intellect alone is not enough because many problems are essentially emotional in nature.
Such as,
He has to handle subordinates, who sulk if they don’t get their own way, Others who can be prickly throw tantrums or under perform for reasons best known to themselves, While some are incapable of working effectively with others.

The ability to handle such problems effectively is heavily dependant on you being able to manage your own emotional state, so that,

1. You stay in touch with your own inner feelings that help you understand your own drives and preferences.

2. You are able to appreciate other people’s point of view and to sense and anticipate how they are likely to respond to any suggestions you might make.

3. You are able to engage with others in a pleasant, mature and considerate way.