Apologies in advance. I'm not in a joking mood. These thoughts are more on the serious side.
We have been blessed by whatever creative force we believe in with a brain and the ability to think. It is a weighty responsibility and too often, we either take it for granted or simply shirk it. Maybe we are possessed of an uncertainty -- when should I think? I would like to present some advice about when to think (besides "always," as that doesn't seem to work for everyone, IBM employees notwithstanding).
The fact is, we are split in two. Religiously, we call the tendency to go against the urge to go against our moral code the yetzer harah or "evil inclination." A more secular mind might just call it a lack of conscience. This idea, that people have two parts which strive is not new. In fact, one could look in Genesis 25:23. Rebecca was told that she had 2 nations in her womb and that 2 regimes which would split off were vying within her. In the next verse, she prepares to birth "and behold! twins!" Why would the text have to say "behold"? Because the prophecy regarding the two nations and two different natures could have applied to a single child, racked with a mature sense -- a positive inclination, and a less mature one, an evil inclination and the two polar opposites would be constantly fighting for dominance within the individual. Imagine how tortured she must have felt until that moment of birth, thinking that her singular child would ultimately lose this battle of conscience and the younger, less mature sense would ultimately win out. At least when she had twins she knew that they would be separate and not have the incessant internal struggle for dominance. It must have been a relief and a frightening thought at the same time.
But we are not twins (except those of you who are). We have those two nations within each of us all the time. We have the capacity for incredible goodness, to create a world, a regime, a nation based in kindness and propriety. We also have the inverse potential for evil. Aside from those few truly righteous or truly evil people, we are constantly torn. If knowing this resolved when to think, then all would be fine and no one would ever be able to claim "I didn't think about the consequences." But that isn't the case.
As a separate issue, we also make connections to other people and we invest some of our identity in how others deal with and think of us. We aren't hermits. We, to varying degrees, allow ourselves to be completed by people whom we respect or fear or whose judgment means something to us. When that person is disappointed, it matters. When someone else is disappointed, we couldn't care less.
When we lie, we are creating a mask, a second self. In the moment when we choose to hide something we create a false front because we want people to think one thing even when we know that the truth is elsewhere. We have established the inwards and exterior man and we hope that we keep the two separate.
So here's the bit of advice: when you are faced with any decision which would require the creation of a false you -- any choice you have to make which will split your identity into a secret one and a public one think about how you would feel if someone you respect or fear were to find out about the secret one. That's your moment of thought. It isn't driven by theological machinations but by your own personal sense of how someone whose opinion of you, you value. Does this mean that this person will certainly find out? No but that isn't the question. Decide how you would feel IF that person found out. Think about that potential -- THAT is when you think. And don't think about the "consequences" of the behavior -- we justify things by saying "no one will get hurt" or "the punishment won't be that bad." That thinking won't help. Instead, think about that person you respect, whose view of you matters.
If you come to the conclusion that IF that person found out, you would be unhappy with that consequence then you should have enough sense to stop. If you truly care about that other person's opinion then knowing that the creation of a separate, hidden identity should be avoided. If, instead you continue the act then your decision to continue, even after that thinking, signals a real problem inside you. You do care and yet you don't. You need to get that fixed. That would be like knowing before the fact that putting your hand in a meat grinder will hurt but doing it anyway because you want to. You are an idiot - if that external judgment of your character doesn't sway you then it never really did and you are cutting yourself off. You deserve whatever consequence you get.
If, after thinking about it, you decide NOT to act, then you are protected. You have used thinking to drive your behavior and to stay safe. If you think about it and realize that that other person would not be troubled by the behavior (and you are being brutally honest with yourself about it...lying to yourself is a horrible thing to do) then your decision to act is perfectly reasonable and have a good time.
But remember, this is only for behaviors that would require that you hide something. If eating a sammich isn't a matter of hiding anything or lying about it, then go right ahead. But if the action will require any sort of subterfuge, you have only a moment to think. You have a brief window to stop yourself and simply think about the way someone else would react if he or she found out about the behavior. Sure, it would be nice to think about the behavior itself and use good judgment to decide how to act, but if that isn't working, then THINK about how someone else would react if he knew you lied or his some behavior.
So clearly, this isn't about having to think all the time about every action and decision. It is about identifying key moments when your choice to hide something or lie about something would be looked at unfavorably by someone whose voice you find important, and it starts with "to thine own self be true."