You have a fan in me Binu John :-)
You have said it rightly.
Only the FIRST step is in one's control--whether it's towards something for a noble cause or taking a bribe or plain murder. Once someone takes the first step, most likely it will never be noticed--whether it's in the positive or negative direction. And that gives the person more urge to move further in the same direction, especially if it's negative--until it's too late to return or even if he/she wants to return, the cost to be paid will quite high--which in all likelihood may have been anticipated by him/her. And in the process, he/she will find/devise ways to make things happen in that direction on a bigger scale. And in the process he/she becomes more brazen so much that they can get away with it--without being caught.
Take the case of any person in the news today [for the wrong reasons]--A. Raja, Ramalinga Raju, Kalmadi, etc, etc....the list could go on. At least Ramalinga Raju admitted in Jan, 2009 when he broke the story of his fraud that it all started with a few lakhs of mismatch in annual audits when they cooked the numbers. And it's now known to all how he did it--quite ingenious one should admit--except that such a brain was used for such devious acts.
Rgds,
TS