Adjective
divisive - Causing disagreement or hostility between people, tending to disrupt unity or harmony.

The election was fought over the deeply divisive issue of immigration, and people on either side of the issue can't see things from the other point of view.
sober - Serious and thoughtful in mood or behavior, not playful or exaggerated; or not under the influence of alcohol or drugs; clear-minded.

It was a year since he gave up drinking and had decided to remain sober all the time, and it took strength to just walk past the bar.