How many of you use "Respected Sir" as opening in official letters like to application in government offices or to your boss ?
Some people do not like "dear sir" becuase they interpret it as real endearment then why they "respect" people who do not deserve any kind of respect ?
Your vote on this answer has already been received
Respected Sir = Used as salutation to teachers/Mentors;
Sir = To Boss, Senior Officials in Public sectors, including Govt.
Dear Sir = Salutation used on Equals. (Dear does not constitute to endearment, in this context))