Hey, thanks, Janis, for the source of the truth saying. And I love that it got itself stenciled onto your wall!
Like many (or maybe most) sayings, this truth one is fabulous and true in theory, and many, many, many times in practice. As a bunch of you noted, the feeling of getting to tell the truth is very relieving. It also has other benefits which you're aware of, like increasing connection between people, lessening loneliness, bettering communication and lessening the chances of misunderstandings.
It's also worth acknowledging what SuperEgg said, which is that there are times when telling part of, or the whole, truth isn't a great idea- or even dangerous or life-threatening. These situations aren't everyday ones- in fact, they're quite rare- but they do happen. And if we are in one of them, we need to be very careful about making the best decisions we can to protect ourselves.
Because life is varied, my general rule of thumb with regard to telling the truth is that I think we ought to always strive to tell ourselves the truth (that's that Step A thing we've talked about before). Then we get to decide what to do next- how much of the truth we want to say at any given moment, to whom, in what way... all those kinds of decisions get/need to be made depending on the circumstances of the moment.
If we try to stay, well, true, to the goal of telling ourselves the truth first and foremost, I've found that the Step B part (what we do with what we know to be true for ourselves) figures itself out. You know, we have to practice making different choices and trying things our and all that... but in general, the Step B follows pretty darn nicely from the Step A, if we do the Step A honestly with ourselves... I know, I know, aren't I SO annoying? I just had to get in that scrupulously honest thing somewhere, didn't I? :)