I’ve always believed that life rewards focus and persistence. If you keep working at something you will eventually make progress. What you have to be careful about is managing your expectations. You also need to take responsibility for the outcome(s) you want and not expect someone else to create the reality you want. Happiness is no exception. Happy people work at being happy and start with themselves first. They have to deal with unhappy moments like everyone else, but have trained themselves to practice acceptance rather than resistance and have fine tuned their own capacity to muddle through and make positive changes.
No one is ever completely protected from the bad things that can happen in life. Each of us will have to deal with disappointment, loss, grief and despair at some point. All we can do is protect ourselves as best as we can through a reasonable approach to risk management and an ongoing commitment to personal growth and development. There are obviously many things we can’t control in our external environments including the actions of others. However, we can increase our internal capacity to manage whatever comes our way.