Life is meant to be enjoyed. Implicit in this statement is that there is a God that had an intention when making life; and then what is meant by joy. To achieve a state of joyousness when in extremely difficult life situations one needs to call upon an inner strength or belief or unique perspective. I think that people have tried throughout the ages to find joy irrespective of the events surrounding them at any time - and once found, some lovingly pass this knowledge on to others.
But this evades the question - Is life meant to be joyful? One likes to feel joy, or love or peace whatever the situation looming in front of them might be - but was it meant to be joyful? I don't think so on many counts. Firstly, the cruelty of nature and death is not joyful - so the intention to make it so was not there, secondly even in situations where physical needs are met, joy does not sit singing happily below the surface.
Should one strive to live a joyful life - yes, as the alternative is pain.