Know when to put down the proverbial shovel and stop burying yourself.
Why is it in life we will not quit inflicting pain on ourselves? When we know we are wrong and just continue planting our feet down, stubbornly holding onto positions that do us no good. Some of the best advice I ever received was, if you take a bite of a poison apple, it's probably a good idea to spit. For some reason that's too difficult, and human nature continues chomping down, bite after poisonous bite.