Having had caffeine headaches in the past, I just take some aspirin + ibuprofin and turn off the lights.
I would expect society would have a bad weekend, and then people would get over it quickly.
Lots of people can get opiates pretty easily, and it's not without problems
If people could buy cocaine at Starbucks (or get cheap stuff at a dollar store), would supply be such a problem for users that they resort to crime?
If caffeine were banned tomorrow and prices rose a thousand-fold, to what lengths would millions of addicts go to postpone the dreaded headache, constipation and lethargy for another day?