This one won't garner much support, but here goes..
I hate it when I get a coughing fit and people keep offering me a glass of water. Even when I shake my head or wave my hand at them, they keep insisting.
I've never understood how a glass of water helps - the tube affected by the coughing fit is your windpipe, and water would go down your oesophagus. You definitely don't want water down your windpipe!!!
I think it's more to do with the feelings of the offerers - they want to be seen to be doing something. And I suppose medics would say 'it's the placebo effect - it feels as though it should do some good, so you relax and the coughing stops' or something?
What I crave when a coughing fit starts is for people not to look at me, not to make a fuss and to leave me alone and not make me speak. That's the best way to help things calm down. Or just let me run away and leave the room , if the situation allows and please, don't come running after me asking about water!!!
Apologies for sounding ungracious.