It seems like an obvious one, but it's easily missed in our fast paced world where a "white" lie sent by text is enticingly easy, and "ghosting" is actually a thing. Our personal integrity and the standard to which we hold ourselves is a measure of our own personal brand value. C. S. Lewis summed it up best with "Integrity is doing the right thing, even when no one is watching".
Integrity is doing the right thing even when no one would know you did the wrong thing. Making the brave choice even when there is an easier opt out to be gotten away with. Being in integrity means being in alignment with your core values even when no one knows the choice you are about to make but you.
When we are acting from integrity it means it's easier to accept the consequences of our decisions. When we do "the right thing" with honour, even if others do not approve or understand, we sleep well knowing we did what was in alignment with our own sense of rightness.
Don Miguel Ruiz, author of the great classic The Four Agreements details the trait of integrity as the number one agreement with self for personal freedom:
"1. Be Impeccable With Your Word
Speak with integrity. Say only what you mean. Avoid using the word to speak against yourself or to gossip about others. Use the power of your word in the direction of truth and love".