Myself I prefer optimistic SF such as classic Asimov and Clarke. I don't mind things going wrong because mistakes are normal. But there ought to be resolution and problems solved by hard-won knowledge and the efforts of good people. If you think that is immoral or unrealistic consider whether you would read your children bedtime stories with no good guys and/or no happy endings. Consider how such children might grow up. Then consider the effect on society of unrelenting pessimism in SF.