Also, "The truth is a valuable commodity that we do not automatically owe anyone." From memory from Smith's "Forge of the Elders" - not an argument from fiction, just that I cannot think of a better way of putting it. Of course there are often, probably usually, good reasons to make accurate information available to others, their actions being based on accurate knowledge generally improves your well being.
Exaggerations are lies, but a specific type, where the basic claim is true, but the statement goes beyond the basic claim in some way for a particular effect on the audience. Exaggerations are specifically manipulative lies.
Excuses are sort of junior grade lies; they may not be actually false, but they do not inform and often mislead. "An excuse is an abdication of responsibility", to quote Rands. If you don't know or if you messed up, admit it. It won't feel good, and won't make you look good; but making excuses just stretches out the pain, and will ultimately make you look and feel worse. If you feel tempted to make an excuse, stop and think about it for a moment, then say something useful about the situation; "I don't know, but I will go and find out".
Each time you open your mouth, you have an opportunity to build something. That’s the perspective you want during the uncomfortable dead silence, not the victim-based emotion of excuse.
I’m in a hurry, but being in a hurry isn’t an excuse for not taking a small amount of time to say something real.
This was partially a response to a post on Less Wrong Lies and Secrets