Learn English – What do you say when you want to join a line (queue )

I think we need to clarify a couple of definitions:

• Native English speaker – A person whose first language is English (they learned English from birth or as a very young child), and for whom English is the primary means of communication.

• Fluent English speaker – A person who learned English later in life (i.e. as an older child, teenager, or adult), and who is very proficient in both spoken and written English.

There is nothing wrong with not being a native English speaker, and many non-native speakers have far better English skills than myriads of native speakers.

It is impossible to answer this definitely without knowing a great deal more about the relationship between you and your interlocutor, but this may be what happened here:

You addressed him with a statement which is ordinarily used by children (and quite young children, at that) to adults they admire. In effect, you adopted the role of a child.

He took this to be intended as a jest, and “played up” to your initiative by assuming the role you assigned him: he responded as an adult (and a particularly elderly adult) would to a child, employing an indulgent and perhaps patronizing tone and the stock language of a stock 1930s or 1940s grandfather.

The word whippersnapper is particularly dated; I cannot believe it has been used otherwise than ironically since the early 1960s. I think for most Americans my age it is indelibly associated with Walter Brennan, the character actor who played the cranky but good-hearted Grampa Amos McCoy on the television program The Real McCoys (1957-63). —Google Ngrams (which doesn't handle hyphenated words well, so I've used the unhyphenated spelling)