I used to have this problem, and I think a lot of people still have this problem—we believe that there is one will of God for our lives and if we make the wrong choice we have skewed the space/time continuum like in “Back to the Future.” In an attempt to never make the “wrong” choice, we become paralyzed and end up doing nothing, which, in the long run, is just as sinful and disobedient.
On the other hand, we become so convinced that God is going to do something that we sit back and do nothing to contribute to the realization of a “God-spoken” plan. Sometimes we need to be reminded that God’s will for us is clearly revealed in the Bible, and His written revelation trumps any feeling or guidance we may have on an issue. We also need to be reminded that sometimes, “disaction” is disobedience.
This is an interesting read…
http://teampyro.blogspot.com/2009/01/stunned-stymied-and-sidelined-by.html
Bekah Mason 
I think that there possibly is to much worry or talk about “finding God’s best” and not missing out on “His perfect will or plan” It is a popular notion: God has “ordered our steps” for our entire life and we can screw up the whole thing at every fork in the road by making the wrong decision. Fortunately God is a God of infinite variables!
God’s will is revisable. He has a perfect will for you no matter where you are in life, even if you’ve taken a “wrong fork in the road.” Through God’s grace, He will even pick up the shattered pieces of your life and make something beautiful out of them. You can’t ruin God’s plan that easy, because it is not a fixed plan. God’s more creative than that. He’s hard to circumvent.
Of course knowing, willful, intentional disobedience (like your murder example) has serious consequences. God still has a will for you — And it is not “second best” either. (How could we ever call God’s will “second best”?) We might lose out on one future–but God can recover us and create another future for us that still brings joy and meaning.