washing my hands of an invisible introduction

[Atop a stairwell buzzing a guy in through the outer gate and and inner door.]

The stranger ascends the wooden staircase as I wait to welcome him to the party. Stranger gets to the top, I extend my hand, we shake hands, he tells me that he is Fred as he continues past me -- hands still in handshake mode -- in search of someone he recognizes. The fucker doesn't even pause to complete proper introductions before asking me if I know so-and-so who happens to be near us.

On second thought, I ought to thank this man for saving me time getting to know anything about him. Thank you, Fred!

idiom: wash hands of