Sometimes social friendships that have a falling out can be like a marriage that ends in divorce. Some divorces can end to being cordial to each other in social situations & get along in spite of the marriage being unsuccessful. It doesn't mean that you would ever get married to them again or what happened to cause the marriage to fail didn't happen or ever really goes from the memory....but it doesn't mean that we can't be cordial to them when out in social situations....but it doesn't mean we will ever have a close friendship like it was either. Being cordial & acknowledging someone doesn't imply that the relationship will ever be more than keeping it at the acquaintance level....sometimes the safest after a friendship blow up.