Yes! Specifically, in TCM the liver holds anger and frustration. Just think of the words associated with the Liver...bile. (in the dictionary: 'derangement of the bile' - peevishness. & It rouses my bile. It makes me angry or indignant. In Latin, biliosus (a bilious man) meant a choleric one. According to the ancient theory, bile is one of the humours of the body, and when excited abnormally it produces choler or rage.)
Think about the words associated with the Gallbladder...'The Gall of that person....' Indignation. (in the dictionary: 'anything bitter, bitterness; asperity, rancour "dip one's pen in gall". "The gall of bitterness" means the bitter centre of bitterness.)
So, all....when we flush we're flushing out all the emotions related to the gallbladder and liver...yippppeeeeeee!!!! Makes sense to me!