Wish You Were Here

Now there's an ambiguous phrase if you like. Like the Spanish inquisition, every time I think I've counted the number of meanings I get another one. So these are not numbered.

It can be what postcards purport to be - I'm having a really good time and I think you'd like it too - a gift.
One step down: is I'm having a pretty good time, but something is missing, and it's you. Then it would be perfect. Yearning.
Further down is: I'm having a poor time but you would perhaps make it bearable. Alienation and loneliness but could be tinged with (faint) hope.
A bit more sardonic is: I'm having a poor time and you might as well be as miserable as me.
And of course: wish you were here and wish I wasn't. Which can have two versions, depending whether you think the addressee would like it.

Roger Waters seems to start in the third one, addressing Syd, but by side two (sorry, habit) is somewhere in the last phase, addressing - who knows. Hopelessness and possible paranoia.

What did you mean last time you used it? And who did you talk to? God?