Festivity: gold 26%, white 23%, silver 15%, …
Heller (1989)

When roundness is connected to symmetry as seen in a circle, it has a meaning in the depth dimension and perceived as cheerful and pleasant. While straight corners are perceived as more serious (Poffenberger en Barrows, 1924). Lakoff and Johnson (1999) saw that there are many proverbs and sayings that have to do with form characteristics and emotions. Round: regulated, completed, ready. (Michiels, I. editorial)

Reward Dependence reflects a heritable bias in the maintenance of behaviour in response to cues of social reward. It is observed as sentimentality, social sensitivity, attachment, and dependence on approval by others. Reward Dependence corresponds with Eysenck’s introversion-extraversion trait.
Low Reward Dependence: independent, non-conformist, practical, tough-minded, cynical, unwilling to share their intimate feelings with others, socially detached, irresolute, insensitive to social cues and pressures, content to be alone, minimally motivated to please others, act for immediate gratification, social withdrawal, with aggressive anti-social behaviour detachment, coldness in social attitudes. Individuals low in Reward Dependence are practical, tough-minded, cold, socially insensitive, irresolute, and indifferent if alone.
High Reward Dependence: sentimentality, Openness to warm communication or social sensitivity, Attachment, Dependence on approval by others, greater need for social rewards and verbal approval, ambitious, warm, warm social relations, sentimental, pleasant, sociable effective communication, sensitive, recognize salient social cues, sympathetic, genuine care for others, socially dependent, persistent behaviours, easily influenced by emotional appeals, learning from reward signals, persisting repetition of actions that are associated with rewards, increased sociability and a need for social approval. Individuals high in Reward Dependence are tender-hearted, sensitive, socially dependent, and sociable.
(Cloninger, 1994)

Square/rounded has an important influence on the function of the size of an angle. Rounded corners are experienced more cheerfully, while straight angles are perceived as more serious (Poffenberger en Barrows, 1924). Round and square are also related to activation. Roundness in parts of utensils or interfaces can indicate a button, where activation is needed. Sharp roundness can therefore trigger alertness and induce action.

Extroverts use less words that express negative emotions, and more words about friends and family. A report of an event will be presented subjectively and with its own interpretation. Extroverts use relatively more adjectives to describe behavior and less concrete descriptive action verbs. They often have lively and cheerful conversations in which they discuss multiple topics in a loose way. Extraverts process information in a global way. A looser way of looking at the world is related to a large degree of interpretation. They speak and respond more quickly in a conversation, but they are less scrupulous about the facts.

While introverts will provide a concrete and factual description, with fewer adjectives and more descriptive action words. They are often more serious in conversations, and focused on one subject. They process information precisely and focused. Introverts thinks well before they speak. This also fits with slower speaking, more frequent breaks and more precise formulation.
Beukeboom (2011)