Your word is your lifeline. If you do not have your word you are nothing. The most important thing is to always keep your word. Fulfill all your promises. No matter how small. Do this and your word will have more weight than gold.
Recently, I had a civilian ortho Doctor ask if I had been airborne when I was in the army. Puzzled ( that was 45 years ago) , I told him that I was. He said the he could tell, because I had what he called "paratroopers knees " !