Many people find the colour blue calming and restful. Generally it is associated with honesty and being trustworthy, as well as imagination and intuition. It is generally considered a masculine colour. Dark blue can be viewed as depressing and give a room a chilly appearance, especially if the room doesn't get much natural light. In some cultures blue is the colour of mourning.
Gazing at a blue sky or looking over the blue sea on a sunny day is calming. Spas often make use of the colour blue to promote an atmosphere of peace and serenity.
I find blue of the right shade relaxing and painted most of the interior walls of my previous house this colour. I would find a dark blue 'cold' but a blue that isn't too pale or too dark makes me feel calm.
Blue is considered to have health benefits including decreasing blood pressure and slowing breathing and heart rate. The right shade of blue is said to help people sleep soundly. These factors are probably why blue is often thought to have healing powers.
Blue is also associated with intuitive thinking, imagination, open spaces, freedom, wisdom and sensitivity. Very bright or 'electric' blue can be considered exhilarating, rather than calming.
In western countries pale blue is often the colour used for clothes and accessories for baby boys. However, I read on the internet, in Belgium it was traditionally used for baby girls. Now, in Belgium too, it is more often worn by baby boys.
Blue plumbago flowers Image by Marie Vonow
Blue often has a connection with spirituality and is said to ward off evil spirits. The Virgin Mary is depicted wearing blue.
Traditionally, western brides wear something blue as a symbol of love, purity and faithfulness. In Portugal wearing blue underwear on New Years Eve is believed to attract tranquility into the coming year.
Dark blue flowers are considered to have a serene tone and calming effect. Therefore they are looked upon as appropriate as a get well or sympathy gift.
Navy and dark blue are seen as elegant, sophisticated and a symbol of intelligence and a conservative attitude. Sometimes these shades are considered old fashioned.
Dark shades of blue or just 'too much blue' can be associated with pessimism, sadness and depression. In some countries, including Korea, Mexico and Iran, blue is the colour of mourning.
People sometimes talk of 'feeling blue' or 'getting the blues' because of the connection between certain shades of blue and sadness. Blues music tends to be sad or melancholy.
Blue is often used in advertising to evoke a feeling of trust. As it can be an appetite depressant, fast food outlets tend to avoid it.
While different shades of blue can have differing influences, I haven't read of blue making people overactive or angry. It seems generally accepted as having a calming influence but if the shade is too dark or there is too much blue it can make people sad or depressed.