All or Nothing

Prescription labels have a lot of information on them. As with all directions, you must obey the entire label, not just the parts you deem relevant.
In college, when friends would skip classes they'd ask for my notes. (I dated each lecture.) I'd hand them every other or every third page just to see if they were paying attention. They didn't.
Whether assembling a bike or installing a ceiling fan, failure to follow each step could prove catastrophic.
Why do people treat medications differently? Why do they stop reading where it is convenient?
Directions read "take 1 or 2 tablets by mouth 1 or 2 times a day as needed for pain". That's what it says. This allows for a maximum of 4 tablets to be taken in a day. Yet this conversation will occur...

Half-Reader: I'm out of medication.
CP: How?
HR: Took them all.
CP: How?
HR: By mouth.
CP: Obviously. I know it's big, but did you put them all in at once?
HR: No. It plainly says "as needed" on there so I took them as I needed them.
CP: But it also says 1 or 2 at a time. And then it says only 1 or 2 times a day.
HR: I don't read that part. All I know is it says "as needed" and I needed them. And now I need more.

Or...
Late Refiller: But it says I have 3 refills.
CP: It does say that. What else does it say?
LR: Quantity 30?
CP: Uh-huh. And after 3 refills?
LR: My doctor's name? Who's not really my doctor anymore because I...
CP: Follow along with the bouncing ball. Now read with me.
"3 refills..."
LR: "3 refills..."
CP: "Until..."
LR: "Until...January 31, 2013". Oh.
CP: Good job.
LR: So I can't get it then?
CP: Not since it is now February 2013.