My long-time friend Phil Wels just put up an excellent post over on Apathetic Thursday titled Disappointment and Expectations. I encourage everyone to sit down and read it as soon as you can.
Here is the crux of the entire thing:
You can only control you. You control how you act, you control how you react. Internally, you have control. You choose to be disappointed or not.
There is so much more good stuff, but I find myself parroting this to my boys are they grow older. It is something I needed to learn when I was younger and still struggle with to this day.
A good reminder.