2012, which seems like a long time ago.
Usually these are along the lines of sporty stuff or loosing weight. I have already stopped drinking alcohol and coffee end of last year and I am doing two hours of activity (as tracked by google fit) already. And nobody will stop me cycling too much anyway.
There are also some things I promise I won't do this year: going vegan, stop gluten intake or low-carb.
Still, some of these might be unexpected.