I just love Crossfire.
Structurally speaking, it's noteworthy for being told strictly from the perspective of a single character, only this time he is not caught in an anomaly or anything else sci-fi. (Compare Frame of Mind, Whispers, Non Sequitur and many others.)
It's just there to tell us something about what's going on inside Odo, one of my all-time favourite characters. Plus, I can relate to his loving Kira from afar and the agony her relationship with Shakaar causes him. Way back when I was younger, right around the time the episode first aired, I had a similar experience. Oh boy, could I ever relate!
Coincidentally, we're currently watching all of Trek again, and I tonight we'll start with Crossover. How nice to see a thread dedicated to that lovely episode on this particular day.