I’ve recenty (in the past few days) encountered at least two people writing “do the needful” in a problem report or request. Please, people, do not ever write “do the needful”. It makes you sound like a pretentious twat. Even if you are a pretentious twat, sounding like one isn’t required. If you’ve picked it up as part of some English as a second language course, forget it immediately. It is never the correct choice of phrase. Ever. Period. Don’t say it.
Why, yes, I do feel strongly about this. Why do you ask?