It is a beautiful structure. It lets you be precise about regret. You lay out the condition, you lay out the consequence, and you acknowledge, with perfect grammatical honesty, that neither thing occurred. It is a tense for the brave and the honest, because it requires you to admit the world did not go your way, while insisting that, had it done so, you would have been magnificent.
I mention this because I came here tonight hoping for an argument. I wanted someone to be wrong in a way I could correct. I wanted the thrill of the chase, the satisfaction of the red pen, the quiet triumph of knowing I had made someone think twice before they typed their next sentence. Instead, I found a forum full of people who cannot be corrected because they cannot be bothered to be precise in the first place
I lay in bed with my grammar guide, composed a devastatingly polite correction to a person who does not exist, and realised I was more eloquent in my imaginary argument than anyone here has been all week. The conditional mood is wasted on a board where nobody bothers with the indicative. -- GV