I struggle a lot with this one...I have been taught that there is opposition in all things

hot vs cold
evil vs. good
hate vs. love
unhappy vs. happy
Etc...

So if we don't know what unhappiness is like how do we know what happiness is?

I'm not sure this is of any help, but I hope it gives you something to think about. I do know that my point for living is different from yours or other people.