PMSL! The end of the 2010s is the 31st of December 2019!
But there are always going to be a few people who insist the end of the 2010s is the end of 2020... Like some said the end of the 1990s (and the end of the millennium) was 31st December 2000. (No, it was 31st December 1999!)
What's wrong with people?! Are they that clueless and uneducated that they seriously believe this???
Do they also count each month as 28 days and believe a year has 13 months? Coz I used to know a woman who swore on her LIFE that there was 13 months in a year, even when presented with concrete evidence to the contrary. JUST because she got paid 4 weekly. Mad cow. Obviously didn't listen at school then.
We've had the flat-earthers, the climate change deniers, and the moon landing disbelievers, (this past few years,) and now we have the 'this decade doesn't end til 31st December 2020' fruitloops. Had to deal with this at the end of 1999 AND 2009!
LOL, I can't believe people are that daft and clueless. Seriously, how can they believe this?
Funnily enough, I don't recall people arguing the point at the end of the 1970s or 1980s. Everyone agreed that the end of the 1970s was 31st December 1979, and the end of the 1980s was 31st December 1989. But at the end of the 1990s AND the noughties AND the end of the twenty-tens here, we have a few people insisting the end of the decade is a year later..
Also it's the twenty-tens, not the twenty-teens. Has anyone ever said the nineteen-teens, to describe the period between 1st January 1910, and 31st December 1919??? NO - it's the nineteen-tens! Also, you say thousands, hundreds, tens, and ones. Not thousands, hundred, teens, and ones. Ergo: this decade we are in (and almost out of) is the twenty-tens.
For your reading pleasure...
en.wikipedia.org/wiki/2010s
Yep, it's from wikipedia, but you can look ANYwhere else, and you will get the same information, and confirmation that this decade we're in now is the 2010s, and that it ends on 31st December 2019 - NOT 31st December 2020!
You're welcome. Now leave your homework on my desk on your way out. 
As for me?? Nothing's going to change for me in 2020. Nothing much different has happened for a quarter century, so I don't expect anything to change when Big Ben strikes twelve at midnight on 31st December 2019/1st January 2020. I am making no resolutions either, as I never stick to them. HEY maybe I will make a resolution to not stick to any resolutions. THAT one I will definitely keep. 