something leaves a bad taste in your mouth or something leaves a nasty taste in your mouth
said to mean that something that someone does makes you feel angry or disgusted with them because it was a very unpleasant thing to do
Some people are abusive in shops, in buses and on trains. They seem to think it is smart. For the victim it leaves a nasty taste in the mouth.
Easy Learning Idioms Dictionary. Copyright © HarperCollins Publishers