In life, lots of things could. Lots of unexpected things. Some good and some bad. This why we need to look into ourselves to really examine who we are. Who we are without friends and family. To examine how inner state.
We sometimes have to remind ourselves and everyone around us about who we really are. Even when things go right or wrong. This is something that should be done regularly to help us stay true to ourselves. So you would not lose yourself in another person or to a job or a situation.