First off, two of my own that I'm kinda proud of...
1 - "Deal with what is." In other words, don't waste time and energy wishing things were different - better job, more pay, etc. At this time, in this place, that is not reality. You have to deal with life as it is. If you don't like it, work to change it in the future - look for a better job that pays more, if necessary, get the education to get that better job, etc.
2 - "I reserve the right to be wrong." This one is pretty self-explanatory.
...and then my all-time favorite quote and IMHO, words to live by.
"A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects."
Robert Heinlein