I considered the alternative which was hopelessness and it made no sense.
The reality is no one gets everything they want out of life. Therefore we're constantly adjusting to the various waves and creating a series of Plan Bs.
All one needs to start is to think about one good thing they have going for them self and build upon that.
Reading inspirational biographies of people who overcame challenges, paying attention to negative "self-talk" and replacing it with what you want out of life. You have to (want) a change.
Associating with positive people, volunteering to help some less fortunate people, listening to your favorite music while working out or taking a stroll through a park or on a beach.
Spending time with friends and family can help to balance things in one's life. Simply doing things you enjoy lifts your spirits.
For others it's their religion or having a spiritual connection that gives them hope. Maybe it's realizing both good/bad time are temporary. One has to keep perspective and ride the waves.
Generally the tendency is to "shrink our world" when we start feeling despair. We withdraw from others and fun activities which only intensifies feelings of depression and hopelessness.
We see people laughing and having good times and convince ourselves that they're different from us or we can't relate to them or them to us. They're too ignorant to see how awful life is...etc
This only makes us feel like "we're alone" but in reality we are the ones withdrawing!
We're not "in the mood" to be around happy positive people. We want to have our "pity party", close the blinds, and stay in bed all day. We're (choosing) to shut light out of life.