I believe that every action has purpose. God doesn't let things happen "just 'cause". It's all a part of his plan. If something doesn't happen, its because He either wants us to wait,or has something better in store for us. I don't feel sad when things don't work out the way I would like them to, I feel happy. Something better that I don't know about is waiting just around the corner for me. I know it's better because God wouldn't let something great pass me by only to give me something crappy.
Just remember, it's all for the best!