Looking both ways...

Romans 14:19-23 Let us therefore make every effort to do what leads to peace and to mutual edification. Do not destroy the work of God for the sake of food. All food is clean, but it is wrong for a person to eat anything that causes someone else to stumble. It is better not to eat meat or drink wine or to do anything else that will cause your brother or sister to fall. So whatever you believe about these things keep between yourself and God. Blessed is the one who does not condemn himself by what he approves. But whoever has doubts is condemned if they eat, because their eating is not from faith; and everything that does not come from faith is sin. 
From the earliest age we are told to look both ways before we cross the street.  The same is true for any decision we make about our behavior - we need to look inside to the core convictions we have, and we must look outside to the impact our choices have on others.  The first is truly the hardest.  When we look within, we often take just a glance to see what our conscience says about some act.  The conscience is not always right; it has been affected by the fall.  So in looking within, we also need to look in the mirror of the Word of God, allow the Holy Spirit to transform our minds and the way we think about things, and ask if that action is Christ-like.  Even when we do all of the above, and find the "all-clear" sign, we cannot simply do whatever we want with a clear conscience if it is detrimental to a brother or sister in Christ. We must not live selfishly.