Your word is your bond
One of the things my grandfather taught me was that your reputation is everything. If you say you're gonna do something you do it. Period. No excuses, no rescheduling, no wishy washy maybe later. I've lost friends over this because I actually hold people accountable to their word and myself to an even higher standard. But you know what? The people in my life know they can trust me completely. That's worth more than a hundred fake friends who bail when it's inconvenient.
Man, this hits home. When I promised the kids I'd build that treehouse, I could've backed out a hundred times, but your word being everything kept me going. They remember that.