There's the issue of highlighting what was bad, and putting the achievements into the background. I'm not arguing with you right now, there have been terrible things happening in 2015, but let's celebrate the good as well, shall we?
Pluto was explored with a probe for the first time and scientists can now work on devising what's really inside the dwarf planet.
The USA and Cuba finally made up and started up new diplomatic relations.
Peace negotiations started in Yemen, Ukraine, Myanmar and Colombia to end some of the longest lasting civil wars in modern days.
The USA debt crisis was kind-of stable for the past years, including 2015. This doesn't mean the amount of national debt faded, it just slowed down with its increase. Yet USA unemployment fell to a wonderful 5%.
Marriage equality gained a foothold in the USA, and is a worldwide agenda right now.
With all this, the fall in poverty rate continued to an extent where the amount of people on the world living in dire poverty fell by 50% since the nineties. There's also a rise in cancer survival rates due to new technology introduced. Most world powers experienced a stable growth in GDP, and India is slowly turning into the next major industrial power of the world with growth slowly exceeding China's.
In some sense, it was a terrible year. In other senses, it was a year of human advancement. Either way, I think it was just another year in human history with both positive and negative events.