Klang's finger
The restaurant scene right after the table (and soup bowl) is bisected, Klang (Leo McKern) holds up his hand to show that HIS finger had been cut off by mistake, McKern holds up his hand, THEN quickly tucks his finger under..this always bugged me, even as a kid I could see that it was a poorly executed gag
...I know it's cool to say that A Hard Day's Night is great and Help sucks (especially if you're a worshipper of His Majesty John Lennon) but I find Help just as entertaining and fun