We cannot always reason with those that are bitter towards us and sometimes we may need to accept that it exists. To counteract this with retaliation is something that needs careful consideration.
"Consider how much more you often suffer from your anger and grief, than from those very things for which you are angry and grieved." - Marcus Antonius
Perhaps we are guilty of hostility more than we would like to be. Greater interaction with people should reduce these feelings. Less anger should result in more confidence and less stress.
Is a discussion possible and is it worthwhile? A few words and an exchange of viewpoints might result in one or both sides having a change in attitude. Try to see another point of view no matter how unreasonable it appears.