Until 1968 it was an unwritten rule of The Beatles that wives and girlfriends did not attend recording sessions. This was unilaterally abandoned by John who insisted on Yoko being with him at all times. The others clearly resented this, especially when Yoko offered unsolicited advice on the music they were producing.
Mostly this resentment was unspoken. But according to Geoff Emerick, it exploded into the open during one particularly fraught recording session for Abbey Road. On this occasion a bed had been introduced into the studio to allow a flu-stricken, Yoko to participate.
"...I noticed that something down in the studio had caught George Harrison’s attention. After a moment or two he began staring bug-eyed out the control room window… Yoko had gotten out of bed and was slowly padding across the studio floor, finally coming to a stop at Harrison’s Leslie cabinet, which had a packet of McVitie’s Digestive Biscuits on top. Idly, she began opening the packet and delicately removed a single biscuit. Just as the morsel reached her mouth, Harrison could contain himself no longer. ‘THAT B**H!’ Everyone looked aghast, but we all knew exactly who he was talking about. ‘She’s just taken one of my biscuits!’Lennon came to the defence of his wife and the two men go. Ironically, Lennon was equally proprietorial about food he took to the studio. When it came to his personal possessions, he certainly did not agree with his more extreme left-wing friends that all property was theft.