Cool colours are calming but used in the wrong way can show indifference. Colours in this space include green which is one of the most relaxing colours in the world because of its association with nature and healing. In commercial design, it inspires innovation.
Blue on the other hand is authoritative and dependable reminding us to tranquility and purity. Do you want to portray knowledge and significance? Use blue.
Purple is associated with feelings of beauty and luxury. It reminds us of mystery, magic and creativity. In addition, it also has a strong religious significance in some parts of the world.