It is true that highly intelligent people always stay calm. They may appear calm and happy at many times and these are all essential qualities. While I’ve run across numerous effective strategies that smart people employ when faced with stress, what follows are ten of the best. Some of these strategies may seem obvious, but the real challenge lies in recognizing when you need to use them and having the wherewithal to actually do so in spite of your stress. 

HERE ARE SOME OF THE WAYS THAT INTELLIGENT PEOPLE THAT THEY STAY CALM; 

• THEY HAVE APPRECIATION AND GRATITUDE FOR ALL THEY HAVE; Taking time to contemplate what you’re grateful for isn’t merely the “right” thing to do. It also improves your mood, because it reduces the stress hormone cortisol by 23 percent. Research conducted at the University of California, Davis found that people who worked daily to cultivate an attitude of gratitude experienced improved mood, energy and physical well-being. It’s likely that lower levels of cortisol played a major role in this.
• THEY STAY POSITIVE ALL THE TIME; Positive thoughts help make stress intermittent by focusing your brain’s attention onto something that is completely stress-free. You have to give your wandering brain a little help by consciously selecting something positive to think about. Any positive thought will do to refocus your attention. When things are going well, and your mood is good, this is relatively easy. When things are going poorly, and your mind is flooded with negative thoughts, this can be a challenge. In these moments, think about your day and identify one positive thing that happened, no matter how small. If you can't think of something from the current day, reflect on the previous day or even the previous week. Or perhaps you’re looking forward to an exciting event that you can focus your attention on. The point here is that you must have something positive that you're ready to shift your attention to when your thoughts turn negative.
   
 

That's something I've observed myself as well, people who are wise tend to show negative expressions such as anger far less. They're instead better at channelizing their feelings and emotions in much better ways.  

I suppose this is because they understand the depth of emotions and can calculate the benefit or harm it would bring them. By nature, anger is an emotion that does more harm to your own self than the other person if blown out of proportion. So, they choose not to waste their energies.  

So, to sum it all up, intelligent people posses emotional intelligence.