As others here have said, ignoring the 'hello' is the best bet. For those on the asking end, my advice is to ask your question and if it goes beyond a simple an

As others here have said, ignoring the 'hello' is the best bet. For those on the asking end, my advice is to ask your question and if it goes beyond a simple answer, follow up with 'do you have time to talk about this now?' Most people assume I have time or desire to answer a flood of questions because I responded to the first simple one, which isn't usually the case.