Pursuing a pointless endeavor; counter productive; beating a dead horse, a cluster fuck, a waste of time.
Matt: I want to fix up my old truck to sell it. It needs about $2000 in work. What do you think?
Jack: I don't even think you could sell it for that much. Seems like a dick mission to me, hoss.
Jeff: I have to convince my boss that we need to cut salaries to just stay in business. It's the only way.
Wendy: He'll agree to that?
Jeff: Oh hell no! It's a total dick mission.