"A habit cannot be tossed out the window, it must be coaxed down the stairs a step at a time." Mark Twain. 

I like this quote, but as a Christian I have seen the Lord miraculously deliver people from the throws of addiction, a life of crime or debauchery, with the preaching of a single sermon, an isolated passage in the Bible or a single conversation with someone. That being said, for every deliverance like that, the majority are "coaxed down the stairs, a step at a time. 
Photo by Jordan Matter