The problem of wholeness:
Some will say that their life is great or positive but does that mean life itself is great or positive as they assume? Life isn't. The notion of life being good depending on the person is completely what we can call selfish. Life is a complete collection and never separated. First, you didn't choose any of your circumstances and even if you struggled to get the "goods", someone else struggled and never got it. Circumstances that you never choose isn't something you made. Not to mention how these good most likely are the product of someone else's misery, one man's misfortune is another man's fortune.
The same inseparable life is giving you the good while giving others the bad, if you say life is good and I don't give a fuck about others, then you are completely selfish. And its not limited to the current people. How much of the advancement and knowledge we have today is only a result of previous people's miseries.
Why people should suffer so some people have "good" life or why should they suffer as a type of expirement.
If you don't accept yourself to suffer then you shouldn't accept others to suffer too. Even if you think "things can change", how many of these sufferers are helpless?
Logically speaking, life is positive if there is no possibility of negativity. Any occurrence of negativity will make life logically negative.
If you like your good life or like struggling against negativity, then its your choice but to say that life is a gift or a candy is an absurd thing. Any suffering or any problem is a product of life and inseparable.