At some point we realize that you're topping out at 6' and won't play in the NBA. Sure, that day was sad, but you saw it coming, and for that reason it was a simpler pill to swallow. Lives change over time and we adjust to what seems reasonably possible.
I realized that my career interests were in a far lower-paying field than one would dream of (education) so any thoughts of some big extravagant house, new car, and eating at Salt of the Earth every week basically went out the window. That's okay, though, because my circumstances have prepared me for frugal living and enjoying the little things. I commute on a bike, try to cook for myself instead of going out, and save my money for the occasional splurge on a good concert. I'll make more money some day, but my circumstances have allowed me to enjoy a life where money is not a driving force.
This idea extends further. In the job search, you will get turned down for interviews and jobs, but the only thing you can focus on is what's in front of you and not that great opportunity that wasn't given to you. That girl or boy that isn't interested in you, it's time to pick up and move on to find that person who is interested in you and worth your time. There's no sense crying about friends who have left, so we must enjoy the ones who are here and take time to visit the ones who are gone. We have to deal with the circumstances that are given to us.
One of my strongest character traits is that I keep things in perspective. I've mentioned plenty of times that God teaches us not to worry because He cares for the birds and the grass and everything in between, so surely He cares for us. Worrying does not get us anywhere, no matter how hard that is to hear. We could mope about the job we didn't get, the girl who doesn't like us, and the friends who have moved all over the country, but mourning our losses won't get us very far. For this reason, I handle death and funerals better than most people. They're gone, so there's nothing we can do now except celebrate the life our friend has lived.
I've been dealt some unfavorable circumstances over the past few years, but the only way to move on is to move on. Things are the way they are, we may not be able to change them, so we have to take the cards we are dealt and move forward. It's a scary concept, but God has our best interest in mind and will carry us through whatever arises in our lives.
Here is a beautiful song by The Head and the Heart singing about the way things change; Rivers and Roads: