To act according to the truth requires you to seek what is best, as far as you understand it. To align completely with what is best is to choose and obtain the greatest outcomes possible for yourself. What could be better? Anything less is “more or less than this,” and is “the spirit of that wicked one who was a liar from the beginning.” (D&C 92:25)
Lying isn’t just a case of devaluing the truth as a whole, but in every case consists of specific examples of valuing something lesser more than something greater. Dishonesty requires you to intentionally devalue what you perceive to be more valuable.
It is dishonest to aim anywhere except the ideal as understood. Dishonesty is the degree to which you think, feel, or act differently from the best you know. It is dishonest to think, feel, or act against your understanding of what is best. It is dishonest to choose something you perceive to be of lesser value over something of greater value. It is dishonest to embrace something of lesser value when something of greater value manifests. Honesty requires you to choose what has the greatest net benefit, and it requires you to actually enjoy doing so. Anything different indicates that you are in rebellion against the truth, and prefer something above it.
When you live in a way that is less than the best you know, or you do things whose costs outweigh the benefits, you are engaging in something contrary to your best interests, and this is dishonest. These infractions can happen on matters large and small. For example, all addictions are instances of the lie of preferring what has less value over what has more value, but so is every form of procrastination.