Imperius, unlike the other two, looks dead useful. Combined with Memory Charms and used with caution, it could open any door in Britain to me. Being put under it was frightening, but since we were in class, Moody didn't ask me to do anything awful. And now I know what that feels like, so I can suss out how it is best used. I also saw how all three curses were cast, and when I was alone, I made a point of practising them. Spiders are everywhere here, and nobody misses a few. I've not had the opportunity to cast them for real yet, and even doing it on spiders and mice takes a lot out of me, but I think I have the basics down. The rest will just take time.