Adages may be interesting observations, practical or ethical guidelines, or pessimistic comments on life. Some adages are products of folk wisdom which attempt to summarize some basic truth; these are generally known as proverbs. An adage which describes a general rule of conduct may be known as a "maxim". A pithy expression which has not necessarily gained credit through long use but which is distinguished by particular depth or good style is known as an aphorism, while one distinguished by wit or irony is known as an epigram. Through overuse, an adage may become a cliché or truism.