I'm enjoying this thread also.
Been so long now since i read my old biogs but was it attributed to the break-up of him & Asher?
Not a breakup, but a lack of closeness that Paul occasionally complained about. John speculated that it had been an argument. In "I'm Looking Through You", Paul said it was when Jane was busy with her job and wouldn't take his phone calls. It makes perfect sense that Jane would end up in some of his songs, since it was a 5-year relationship that never quite got together.
Paul once said that he could write a song about anything, it didn't have to have been personal, he could have read something in a book or newspaper. Whereas John always said that it had to come from within, he couldn't just make up a love song, for instance, if it hadn't happened to him.
I'm surprised John would say that, since he and Paul "wrote to order" for many years, and many of these completely made-up songs were big hits. But then, John delighted in contradicting himself. (John did prefer, at least in retrospect, those songs that
were personally meaningful.)
In Paul's autobiography he points out at least twice that he writes songs that were completely made up, whereas George had to feel the subject was somehow personally meaningful (he was distinguishing his style from George's). Paul was pleased to be able to write songs based on nothing; I guess he saw it as being extra flexible.
I happen to like personal meaning in a song, which is why I suppose I'm drawn first to George (who was always sharing his thoughts) and then to John (who often shared his thoughts, but sometimes in a cagey way). Paul has written some great tunes that I find really moving. "For No One" is one of those, so is "Elanor Rigby". But even great songs like "Let Me Roll It" and "Nineteen Hundred And Eighty Five" just can't hold my interest because there's just not enough to them. It's like, I would have to make up the whole meaning myself; the lyrics themselves don't culminate in anything.
I guess it's like appreciating some forms of modern art. People say, "Ah, I see in this smeary canvas a great conflict between good and evil!" I might say, "I wish the artist had taken drawing lessons". When someone shares their ideas with me, I prefer to know what the ideas are. So often Paul's music to me is sort of like popcorn. It might be a pleasant experience, but it doesn't fill me up.