hill to die on

Etymology
An allusion to the instances where a military doggedly pursues a goal or defends a position no matter the cost or (lack of) benefit, typically involving a hill (high ground). Examples include, , and.

Noun

 * 1)  An issue to pursue with wholehearted conviction and/or single-minded focus, with little or no regard to the cost and no intent of equivocation or compromise.

Usage notes
Often but not always used in the negative or interrogative, as in “I strongly disagree with their decision, but it’s not a hill I’m willing to die on”, or as a question such as “If you do this, many people will get angry (at you). Do you really want to die on that hill?”.

Can be used to express your opinions over-dramatically: "Donald Glover is the best SNL host, and that is a hill I will die on."