Probably the one I depend upon the most and pass along to my kids, my friends, is "consider the source". We spend so much of our lives worried about what others say, or reacting to what's said to us, following someone else's direction or idea of who we are, what we should be doing, etc.

At some point, I think we need to take that in but "consider the source" before we react. When I started to do this in my own life I found a lot of freedom. Now I'll take someone's wisdom or even a mean comment but I'll balance it off with what I know of the "source", what motivation they might have, what experience they do or don't have, even why this specific person said this specific thing (their motivation perhaps) and then go from there.