Your fundamental premise is contrary to what the Bible teaches. God's judgments were *never* "because they offended me." It's a matter of right and wrong, and therefore corruption and evil, not mere offense. The prelude to the flood says "The Lord saw how great man's wickedness on the earth had become, and that every inclination of the thoughts of his heart was only evil all the time" (Gn. 6.5) and "the earth was corrupt ... and full of violence" (Gn. 6.11). We all know that any judge worth his salt on the bench vindicates good and judges evil—that's what he's there for. Otherwise evil proliferates and society self-destructs. The point of the courts and police is to enforce morality and to pronounce sentence on the guilty. This is what God did, and its perfectly moral. A judge never rules, "Well, that's offensive to me, and therefore you'll serve prison time." Nor did God. It was because the perpetrators were guilty and deserving of punishment—just consequences for their behavior.

So if I emulated the actions and emotions of Old Testament God, then would I following the moral code you believe is proscribed by his character, actions and teachings? Thus being completely moral? Because it feels like smiting entire villages... or the whole world in a flood even, because they offended me - would not be moralistic by any standards let alone the Bible's.

Neither. According to Christians, morality is based in the character of God. What makes something right is if it conforms to his character/nature. We believe in objective morality, meaning that there is such a thing as right and wrong because it is based in an objective standard. Saving a life is moral because God is life and has invested us with the image of God. Taking life at certain times can also conform to certain aspects of his character (judgment, for instance). Our motivation doesn't always count. We could do the right thing for the wrong reasons, but it's still the right thing to do. On the other hand, if our motives are right, even if things don't work out right, we acted morally. So morality is in the plumb line, and not necessarily either in our motivation or actions.

Are some actions always moral or immoral regardless of motivation, or is it possible that any action could be moral or immoral depending on the motivation? For example, you end someone’s life because it is the only way to prevent them from doing the same to you or an innocent. Is the action still immoral? Or a second example, you save someone’s life only because you wish to exploit them for selfish reasons. Is the action still moral?