I'm with Ronnytron on this. I've always been told to make plans but don't plan results. That is what causes disappointment.
But, I still do sometimes. So I shift gears. I then start trying to think things didn't go my way for a reason. Maybe I did something wrong, which, by the way, is all I can control. Or I'm not so fast to be disappointed because the result may end up better than I had hoped for. How many times has someone said that they lost their job. And because of what seemed to be a horrible thing, turned out to be the motivation they needed to find something much better, they now call it a " blessing in disguise" rather than a disappointment. Things don't always go that way, but that mindset can delay disappointment long enough to implement plan B. For me, disappointment can lead to giving up and to me, that's not an option.