The song is about a breakup, and it starts with the person hearing from their "ex" (So now you send me your hardened 'regards', When once you'd send me 'Love') who is just sending a friendly letter.
This stirs the person's feelings for the "ex" and they move between depression ("Having learned my lesson, I never left an impression on anyone") to anger they were dumped by them ("REJECTION IS ONE THING, BUT REJECTION FROM A FOOL IS CRUEL").
I think you're right, AshesInTheSky.
The song is about a breakup, and it starts with the person hearing from their "ex" (So now you send me your hardened 'regards', When once you'd send me 'Love') who is just sending a friendly letter.
This stirs the person's feelings for the "ex" and they move between depression ("Having learned my lesson, I never left an impression on anyone") to anger they were dumped by them ("REJECTION IS ONE THING, BUT REJECTION FROM A FOOL IS CRUEL").