It all started with ancient Greek philosophers, like Plato, who valued stoicism and a stiff upper lip.
Plato believed that emotions were not for showing and that they should be controlled, mastered and kept under wraps.
"Plato characterised emotions as being destructive forces that took control of people, and I think to an extent, that idea continues today," says Dr Peter Koval, from the Melbourne School of Psychological Sciences at the University of Melbourne.
"Emotions have been characterised as very disruptive and as possibly leading to mental illness and the downside of this is that we can often be scared or cautious of expressing emotions and of acknowledging our own feelings."
But Dr Koval argues that in fact, expressing and exercising emotions can be important for our physical and emotional wellbeing.
While we may try to keep feelings at arm's lengths, emotions are a useful barometer and sometimes a warning signal to show how we are travelling through life at any moment.
"When we experience an emotion it's an indication that our brain has detected a change in the environment relevant to our wellbeing or our goals and concerns. It draws our attention to those things," says Dr Koval.
"Often people can experience strong emotions quite unexpectedly and that will be a catalyst for them to pay attention to what is going on at that time. It flags something important is happening that they may not have realised. And the intensity of the emotion strongly correlates to how important a situation is for us."
Emotions affect our everyday interactions
Whether we see ourselves as an emotional person, or as a steelier character, emotions are involved in almost every facet of our psychological make-up and of our daily lives.
From birth, our relationships hinge upon a series of emotional exchanges.
"Babies express what could be described as primitive forms of emotions and their caregivers respond to them and express emotions that infants then respond to. We like to think business relationships are purely rational and calculated, but often people listen to their feelings when making business decisions as well," says Dr Koval.
"It's hard to imagine what life would be like without the capacity to experience emotions."
How openly emotional we are – or aren't – is influenced by genetics and how we're taught to deal with emotions during childhood and adolescence.
Culture can also play a role.
In Eastern cultures, the clinical prevalence of depression and anxiety is lower than in Western countries, although they experience just as much negative emotion.
Dr Koval says research suggests this may be due to differences in how emotions are approached, with people in Eastern cultures more accepting of the fact that feeling happy, excited and energised is always balanced with moments of feeling upset, sad, anxious and lonely.
"By accepting unpleasant emotions and seeing them as a valuable part of our psychological experience, they tend not to go to emotional extremes," explains Dr Koval.
Is emotional stability actually important?
Rather than emotional stability, Dr Koval believes emotional flexibility that allows us to express emotions in an appropriate way is better for us.
He says studies have found that people whose emotional responses are more predictable, tend to be more depressed, unhappier with their lives and have lower self-esteem. Emotional stability can lead to emotional inertia or inflexibility.
While it's natural and healthy to respond to an event with emotion, such as feeling angry when a partner upsets us or when we feel we have been wronged, we need emotions to return to a baseline afterwards. So, we emotionally respond but recover quickly.
A sign of emotional inflexibility can be ruminating over an issue. Someone makes an innocent and off-the-cuff comment about your work or appearance – and instead of letting it go, you dwell on it… and dwell on it…
"There's a tendency for negative emotions to take on a life of their own, and once they go in a particular direction, they gain momentum and don't turn back to baseline," says Dr Koval.
"You chew over negative thoughts repeatedly, get sad and get stuck in a negative pattern of thinking 'Why is this happening to me? What is wrong with me?' There's an idea that if your emotions are inert or inflexible, you may be unable to adapt to changes in your environment and to modify your emotions in line with the situation you're confronted with."
How to learn from your emotions
So how can you give your emotions a workout?
Using some of the techniques that are part of acceptance and commitment therapy is one option.
"It encourages people to accept their unpleasant thoughts and feelings without trying to push them down. At the same time, it encourages people to strive towards personal goals that align with the values they hold dear," says Dr Koval.
"It is about increasing emotional flexibility to respond to any situation you are confronted with in a way that aligns with what you want and how you want to behave."
Acceptance and commitment therapy encourages people to come to terms with a situation or event and the unpleasant feelings it triggers. Make space for those feelings instead of trying to push them away or avoid them.
Experts say when we stop giving unpleasant emotions undue attention, they become less potent for us. Let emotions wash over you without acting on them and recognise that you may not be able to control a situation, but you can control how you react and feel about it.
Acceptance and commitment therapy also stresses the importance of clarifying your values – the kind of person you want to be and how you want to behave.
"This is about responding to a situation but engaging in behaviour you want to engage in, rather than getting carried away," says Dr Koval.
Notice how you are interpreting your emotions and current situation – and do a reality check. Are your interpretations accurate? Or are you over-reacting?
Mindfulness is also a useful tool to build emotional flexibility. It encourages people to pay attention to their emotions – good and not so good – without judgement. It is also about staying anchored in the present and riding out emotions while staying calm.
Simple exercises to try
The Black Dog Institute recommends mindfulness techniques, including a one-minute exercise where you time yourself with a clock or watch and, for a minute, focus all your attention on your breathing.
Or try a de-stressing exercise. Sit upright and ask yourself, 'What is going on with me at the moment?'
Note your upsetting or negative thoughts, and then imagine them floating away from you. Breathe slowly and calmly throughout.
See yourself as a witness to what you are feeling and seeing, rather than someone caught up in the middle of those feelings. It won't happen immediately, but the more you practise mindfulness, the easier it becomes.
"We won't all be equally emotional or expressive," says Dr Koval.
"There are times when it isn't appropriate to express negative emotions – in a job interview you don't want to let people know you feel unprepared and unable to deal with pressure, for example. But we need to express our emotions in a situationally appropriate way. It's that ability to shift our emotions to meet the situation which is really crucial for our wellbeing."