We used to think that a lot of things were universal truths. 

And then we started to see that several of these were relative to our frame of reference - including time itself.

The meaning of life, the purpose of why we're here, our values, etc are all not universal truths. 

Each of us chooses what works best for us and lives by them.

The problem arises in two situations.

When we believe in someone else's choice as the universal truth and try to live by it, even when it contradicts who we are or what we want. 

And in a worse way, when we believe that our choice is the universal truth that everybody else must also follow.