Be nice & ask them if they wish to delay the flt. If on a turn around. If they say no carry on what you were doing eg loading the fmc. If they then start to ask more or ask for docs ask the same question & add for flight safety reasons you should not be distracted carrying out flight required tasks. So when they say ok we delay the flight stop what you were doing & give them un divided attention.
Works every time but be nice & you'll find they won't be asking questions as they have to explain the reason for the flt delay.
& yes they are only doing their job but it should not mean distracting you from a flight related task.