The Unfriend

The Unfriend by Dr Who writer, Steven Moffat.
Written by Steven Moffat, The Unfriend is a comedy play about Peter and Debbie, a middle-aged English couple, who befriend Elsa, a friendly American woman, while on holiday. They promise to stay in touch with the politeness of the English and are horrified when she unexpectedly shows up at their suburban home a few months later.
The play revolves around their attempts to get rind of their unwanted guest while struggling with the social obligations and politeness preventing them from simply asking her to leave.