After listening to "Yesterday" recently, it occurred to me that one line didn't sound quite right. From the second verse: "Oh yesterday came suddenly." The thought I had is, given the context provided by the other lines, shouldn't Paul be saying that "yesterday," in fact, "left suddenly." Let me elaborate. In the lyric, Paul describes "yesterday" as something positive, a time when all his troubles seemed so far away, a time when he was with the girl he loved, a time which he believes in and longs for. "Yesterday" only became "yesterday" after his lover broke his heart. And she seems to have done so in a rather abrupt fashion: "Why she had to go/ I don't know/ She wouldn't say." It took him by surprise. Thus, this period of love and contentment - "yesterday" - was taken from Paul unexpectedly; that is, "yesterday left suddenly."
Using the rest of the lyric as a guide, it isn't clear to me what Paul means by the line he used. Any thoughts?