Arthur, speaking in a cold voice upon first seeing Zaphod on The Heart of Gold spaceship:
"We've met, haven't we Zaphod Beeblebrox -- or should I say ... Phil?...
"You'll have to remind me" said Zaphod. "I've a terrible memory for species."
"It was at a party", pursued Arthur [text left out]
"A party six months ago. On Earth ... England ..."
"London," insisted Arthur, "Islington."
"Oh," said Zaphod with a guilty start, that party."
So Ford is upset because Zaphod was on Earth while Ford spent 15 years desperately waiting to be rescued. and Arthur is upset because he was pursuing a particular girl when Zaphod interrupted Arthur's "plying her with a bit of talk" saying he, Zaphod, was from another planet -- and Arthur "never saw [the girl] again".
Until now that is, because it turns out that the girl, whose earth name is Tricia McMillan, is actually Trillian, who, as she says, "hitched a lift" with Zaphod.
Needless to say Arthur isn't happy. [chapter 13]
So in honour of Arthur's terrible time at the party, I offer Lesley Gore and It's My Party and I'll Cry if I Want to:
And a more traditional party image with a quilled balloon, and candy and confetti (which are on the paper):
Hope everyone has a party of a week!