Man has massive headaches that force him to stop doing whatever he is doing, sit down, and pray for them to end. These happen transiently and often.
He goes to see his doctor.
He sees doctor's med student instead.
Med student notes he has had blood pressures of 200/100 in the past. Last visit was one week ago and he had a blood pressure of 160/100. Med student decides to check his current blood pressure, it is 160/100. High blood pressure causes headaches.
Med student asks man if he takes his blood pressure medication. Man says no. Med student suggests he starts.
Med student asks man if he smokes. Man says yes, 1 pack/day. Nicotine causes vasoconstriction which increases blood pressure. Med student suggests he stops smoking.
Med student asks man if he has caffeinated drinks. Man says yes, 1 pot of coffee/day and 6 pepsis/day. Caffeine causes vasoconstriction which increases blood pressure. Med student suggests he stops drinking coffee and pepsi.
Med student is jaded because he has heard hundreds of stories about patients being given good medical advice and ignoring it.
Man comes back next week. He quit coffee and pepsi. He cut smoking down to 1/2 pack/day. He started taking his meds. His blood pressure is 130/90. His headaches are gone. His med student is not jaded anymore.