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I use "sir" or "ma'am" where appropriate as a jesture of respect. The only "dear" I use is in reference to my wife of 48 years. If I preface or suffix that term with colorful metaphors please don't tell her : ) I think the unusual use of prefixes like dear here are by people whose first language is not English and sometimes the @handle is not gender specific or maybe they take it for female. Just guessing...

That happens... But it's mostly sir. :D

Could we have a combination of those? Would you prefer "Dear Sir" or "Sir Dear"?