Deadpan Conversations: The Semi-International Edition

(Scene: A bustling Post Office, in which the day before I had bought some Euros, and today was coming to buy some more)
Post Office Man: Hi.
Me: Hi.
POM: Euros?
Me: Oh. Yes please.
(We then deal with the mechanics of buying Euros, the dazzling thrills of which I will spare you.)
POM: They've gone down today. Yesterday it was 109 for £100, and today it's 110.
Me: I should have waited for tomorrow.
POM: Maybe.
Me: But that'd be gambling, right?
POM: I cannot guarantee anything.