Sometimes a person has a bad or unpleasant experience with another person.

VOA: special.2010.06.20

He might say that experience "left a bad taste in my mouth."

VOA: special.2010.06.20

"This year it is very important for us to in a consensus, we decide together, not to look for war and not to repeat the bad experience we had during these last 10 years,"

VOA: standard.2009.08.27