I gave up smoking after reading really scary stuff about the theories as to exactly HOW it could give you cancer - somehow it seemed more real than "it just does". Never fancied a fag since (well except for the very occasional O.P.).
I've just applied the same technique to drinking (which I do [I mean did] to excess). Having read about the details of HOW it nackers your liver etc, I haven't fancied a drink all week.
If you don't do these things to excess (or are willing to take the risks) then I think there's no real desperate need to quit - but if you know you are doing yourself some damage then the "frighten yourself shitless" approach is worth a try.
Good luck to all change-makers.
ANd specially good luck to you nutty. Keep it up!

Kris