One thing that I am not very good at is accepting the fact that others will not do what they have said they will do. It makes me cranky, though I will say that age has sanded my edges a bit ... it's just par for the course. If someone says s/he will do something, I like to believe it. And then, when s/he doesn't, I feel let down. A promise is a promise in my mind. It's OK with me if someone changes course and takes responsibility for not doing what had been promised. But letting things just fade away into a hoped-for forgetfulness ... well, the edges are not so sharp as they once were, but I can't deny the fact that the edges still exist.
Not long ago, for example, at the suggestion of a friend, I wrote to a man who is well-placed at an Internet company. My friend suggested that this fellow might be willing to lend my son a hand. My son is studying Internet gizmology in college and I thought this fellow might give him a hand. The man wrote back saying he would indeed be willing to help, but that he was very busy and would get back to me. When he didn't, I sent one last request ... as unpushy as I could make it. And again he wrote to say he would help. And now the time has passed and my son's time-window has closed. Naturally, I am sorry I could not help my son in this way, but I am also forced to acknowledge my mild resentments.
So I re-encourage myself: Don't promise what you won't deliver. And if you do promise and don't deliver, then own up to it. Life is easier that way.