What's been the toughest problem you've had to debug so far this year? The problem doesn't have to even be a technical problem. It can be a "people" problem.
There are a lot of people who love both JS and UX/CSS. If we stop labeling people just as “JS developers” or “UX developers”, we can achieve a ceasefire in the current “JS vs. CSS” war and achieve a mutually benefiting peace.