It took me several decades to realize that Dylan’s Motopsycho Nightmare was not just a travelling salesman joke, but a Psycho joke, despite the title, the reference to Tony Perkins, the shower, and the swamp. And it’s not like I haven’t seen Psycho a bunch of times.
But at least I did get Back in the USSR - one of the better Beach Boys songs, actually. 
Kind of like a band named “Free Beer”.
“Tonight: Free Beer”
Actually, I see people as saying it very seriously (myself included), ignoring the duhness of “of course it’s in the last place you look”. I mean it as “it’s always in the last place you’d expect”.
Right! It’s in the last place where an educated guess indicated it might be. If it hadn’t been, then you would have started casting about randomly, but luckily, it was in the last logical place. Like looking through 40 boxes, and after the 39th, saying, “Well, it can’t be in the 40th, but I’ll look anyway,” and there it is, in the 40th.