Meaning of "Goodbye my only friend"
Based on Portal 2 ending song Want You Gone
There is one "Trivia" which i do not agree
''When GLaDOS talks about her "only friend", she is referring to Caroline, Cave Johnson's assistant and the woman that GLaDOS' AI was originally based on.''
In my opinion, GLaDOS is talking about Weighted Companion Cube, not Caroline.
My hypothesis is this When GLaDOS was created, the development of her personality was stimulated by the tests. I assume that one of the foundations when she was created, was to develop the empathy in her. For this purpose Weighted Companion Cube was introduced to tests, by Aperture scientists. Many years later, GLaDOS used same Cube for testing Chell empathy.
Besides, GLaDOS is not saying "Goodbye" to Caroline, after all the verses
''Now little Caroline is in here too
One day they woke me up
So I could live forever''
it's clear that Caroline is now conscious and active part of GLaDOS, so no point to say her "good bye".
Conclusion 3 objects left the complex
2) Portal Gun
3) weightend companion cube
Important detail-Cube was thrown out as the last, as if GLaDOS was not sure of her decision.
Sorry for my bad English.