You expect quite a lot from your children. It is not enough they hold the values you see as good; they must also be able to recognize every situation in which the values apply and to act consistently with those values. They learn to convert their memorized values into behavior and actions, to compute a behavior response to a situation consistent with their values.
Your children of all ages continually go through the process of computing appropriate and effective behavior to go along with their values. Occasionally, you become upset because their behavior is inconsistent with their values. You say, "Why did you do that? You know better than that." They say, "I know I should not have done it, but I did not know what else to do at the time." You might say, "But you should have known what to do." This is, not necessarily true. Your child would have only known what to do if she had been exposed to a similar situation in the past and had computed an appropriate or effective response. It may be this is the first time your child has been confronted by this particular situation or one similar to it.
Yes, your children do have appropriate values, but may need some time and experience to figure out what to do in a particular situation. When your child says he does not know what to do, realize you are dealing with a difficulty in computing the appropriate behavior. With a novel situation in particular, he probably cannot figure out a better way of dealing with it. Respond to this as a learning opportunity and try to help him think of behavior or responses which might have worked out better. The next time this type of situation comes up, he then has some experience that increases the likelihood of a more appropriate response. Perhaps your rule should be your children are allowed to do most things wrong at least once.
All learning for your children relates directly to being able to compute behavior and actions in specific situations or under unusual circumstances. The main thing you can help your children do is slow down, think things through, and plan ahead. In a value- significant situation, when children are unsure what to do or how to act, the first step is for them to calm down. Once they have slowed down, they can think things through. As part of this process, they should look to the future to see how various actions might work out. They learn to mentally rehearse various actions and, in their minds, they learn to anticipate outcomes. Once they are able to do that, they are in a much better position to decide what behavior is and is not consistent with their values.
For example, your grade schooler knows she has more arithmetic problems to do. She can mentally rehearse various alternatives. One alternative is to play a game on her computer and then get her work done after she plays a while. As she thinks about it, she can decide whether that is consistent with her values. Your adolescent can quickly mentally rehearse his various options as a response to his sense of responsibility when a friend suggests smoking. There may not be a clear-cut right way to deal with the problem. Nonetheless, he can briefly look at the options occurring to him and see how they might turn out. Based on the mental rehearsal, he can choose how he will deal with it. At a minimum, he can feel comfortable knowing he really did stop to consider several options and chose the one he thought best, even if his friend decides to try smoking.
If your child is able to say she really thought about her options carefully, and chose the one she thought best, she has remained faithful to her values. This is the real issue with your children. Be not too harsh nor too critical when their actions are inconsistent with your values, if they really have made an effort to think things through and have tried to act consistently with their values. It is unreasonable, nay abusive, to expect your child always to do what is right and good.