Katsuni
Faith is akin to a hope, not to a guess. Choosing to help someone because it helps oneself is still the right thing to do. We all have a subconscious where most of our psychic activity takes place. Nobody can truely know the reasons why he does something. He can make rationalizations but he can never know the truth of it. Therfore you are always right if it turns out to be right!
Unfortunately faith can also lead to horrible atrocities under the blind hope that yeu're right. I'd rather have a little common sense tied into it.
Now the point that yeu may never know the reasons for why yeu do something, is however, an interesting point at that. Generally speaking, it'll always come back to a self serving purpose of some kind or another; if it didn't, we'd die out as a species, we're built to be greedy or self centered in one way or another, however... there is the capacity to extend the "self" to others by proxy in some situations, which is usually where the difference between "good" and "evil" comes from.
Not always, of course, as good and evil are variable terms, rather than absolutes. But for the most part, being kind to someone other than yeurself is usually deemed to be a nice thing to do. Unless yeu're in a heavily racist area and help someone of the 'wrong' nationality, then BAM it's evil. There's a few other sad cases such as that.
The biggest problem with being 'right', is that it's still a subjective term for the most part. In terms of math? Sure, there's a "right" answer, though in that case it literally does mean if yeu came to the 'right' answer the wrong way, then it really doesn't work. In other situations, the "right" to do something, doing the "right" thing, or human "rights", and even "righteous" if we're going to go that far, are all subjective.
As such, arriving at the correct destination, according to someone else's subjective view, really doesn't matter all that much if yeu got there via an abhorred method. Case in point: hitlar did the "right" thing by trying to pull his country out of a massive death spiral. He succeeded, and was right in doing so. Except... he went about it in the wrong way, by using others as scapegoats to generate morale which was missing, and this led to some rather horrible acts we'd mostly like to avoid thinking about. But even that... the reason for why he did things the wrong way was because he had the wrong reasons for doing whot he did; when it was just to save his people it was fine; when it changed to doing it to be better than everyone else, that's when things turned the wrong way.
If yeu have a destination in mind, make sure yeu have the right motives, or yeu'll generally take the wrong path to reach it.
After all, life's a journey, not a destination. There's many destinations along the way, but once yeu reach one, yeu just find another, but yeu never cease the journey, so therefore a destination is merely a place to rest or a direction to go, but the path taken is far more important in most cases. That or the path not taken but then we get into some weird existential stuff =3