Curses seem to be, for a lot of people, the spell that doesn't always work. And old Bellatrix is right, without intent, anger and even hatred, your curse will flop like a pancake. This is where many first time curse castors go a bit wrong. They tiptoe timidly round the whole concept, they kind of want to get their own back without being TOO bad. Forget it. If you are thinking like that then you are wasting your time and to be honest you probably don't really want to be doing it anyway. Its either not right for you or not right for the situation. If there is no anger and hatred to summon up, save your breath.
The thing is that anger and hatred don't turn up all that often. I can honestly say with perfect truth that I have never hated anybody in my life, past or present. People regularly irritate and frustrate me but never enough to generate anything even close to hatred. So for me, the curse would be a rare piece of magic indeed. And also, for me, when I do end up in confrontation it has to be a fair fight. I don't abuse my managerial position at work by bullying my staff and I don't abuse my craft by resorting to extreme measures for trivialities. I also believe it is really important to consider the fact that no matter how justified I think I am, or how much I believe someone may have wronged me personally, I am too involved in my own life to view it dispassionately. I can never be completely sure if I am the hero or the villain. So with this in mind, I think it prudent not to use magic "against" people I know.
A lot of the Traditional witches I know personally will disagree with me when I say that curses are over used by some. To some witches I feel it is too much of a lightening reflex (in honesty I am more likely to slap someone who annoys me as my immediate reflex). It reminds me of the old saying about using a sledgehammer to crack a nut. Why would you bother? I also feel pity for anyone who goes round with that level of hatred in their soul all the time. That must be a hard way to live your life.
That's not to say that curses don't have their place. When I'm not involved in a situation and I can view it objectively, I feel a lot more comfortable using more aggressive magic. I was recently shocked and appalled at an animal cruelty article I read on the internet (no details here, we all know what goes on in the world). I brooded over it for a couple of days and I could feel the anger building at the thought of such totally unnecessary cruelty toward a defenceless creature. Animal cruelty really sickens me. So I made the decision to curse the perpetrator. I summoned my derision and disgust, focused it and cursed the living daylights out of him, (If its worth doing its worth doing properly). To be honest, I felt pretty morally justified in doing it.
Oh and yes Bellatrix, I really meant it....