Plastic Manners Edit Meaning

1.

When two people, or groups of people, meet up unexpectedly and instantly hide their true feelings about each other under awkward and blatantly fake politeness.

After just leaving an unwanted conversation and joining another with a genuine friend:

Newcomer: God, I thought that would never end.

Friend: You two have seriously plastic manners. Just admit you don't like talking to one another. It's sad watching you two stumble through a conversation.

See fake, false, two faced, backstabbing