But Scott, the concept of Grace was originally that God chooses beforehand who will be saved and who will not. BUT, if you displease Him, He might change his mind, and put you on the 'not saved' list. Likewise, if you were originally not on the list, and lead your life to please God, He might reconsider and save you after all.
So I've got two questions:
1. Why are you so sure you'll be saved though you sin, and
2. Being less bad is better than being more bad. Lest God take you off the saved list, shouldn't try to please Him?