No worries

Linguistic experts are uncertain how no worries became utilized in American English; theories include use by Steve Irwin on the television program The Crocodile Hunter and usage by the United States media during the 2000 Sydney Olympics.

[11] Anna Wierzbicka comments that the expression illustrates important parts of Australian culture, including: "amiability, friendliness, an expectation of shared attitudes (a proneness to easy 'mateship'), jocular toughness, good humour, and, above all, casual optimism".

[citation needed] Wierzbicka writes in her book Cross-cultural Pragmatics that the expression "permeates Australian speech", "serves a wide range of illocutionary forces" and displays a "casual optimism".

[15] The phrase has been used widely in British English since the late 1980s, a development partly attributed to the success of Australian soap operas such as Neighbours in the United Kingdom.

One possibility not mentioned in the source is the prominent position of this phrase in the lyrics of song "Hakuna Matata" in the popular 1994 Disney film The Lion King.

[23] Linguistics professor Kate Burridge writes in her 2004 book Weeds in the Garden of Words that expressions including "no worries", "absolutely", and "bottom line" have become less prevalent in favor of newer sayings.