How often have you begun a telephone conversation and never ended up getting to the point, always wondering how to signal to the other person that you consider pleasantries complete or unnecessary, and that your wish to proceed to the business end of the conversation? "Let's get to the point", "cutting to the chase", "what can I do for you", and such phrases have an air of abruptness about them. "What can I do you for" is a lot more congenial, but works only with those with a certain degree of refinement.
And that, gentle readers, was why the intelligent residents of the South of India invented the phrase "Tell me". "Tell me" can be inserted anywhere in the middle of a conversation, and is instantly interpreted as a gentle polite signal to get down to business without the avoidable abruptness of the more correct turns of phrase. "Tell me", therefore, is sheer genius.
After having incorportated it into his vocabulary, rather reluctantly at first, the Mad Hatter is happy to report a 32% reduction in average conversation time over the phone, with 0% unsatisfied interlocutors. Your mileage may vary.
But I'm telling you sir, it's a 100% first class phrase only.