finish on a sour note

To conclude (something) with some particularly unfortunate, unpleasant, or disagreeable piece of news, information, or conversation. The firing of our head coach really finished our football season on a sour note. The CEO's speech at the Annual General Meeting ended on quite a sour note when he announced that there would be company-wide pay cuts and layoffs. A: "You thought the concert ended on a sour note?" B: "Well, yeah—they didn't even do my favorite song as part of the encore!"