For a genuine magician/witch/mage/etc., casting a spell is something like trying to aim an arrow at an invisible target — even if you’ve hit it, it can be hard to convince anyone else of the victory. I’ve known many people who perform spells for anxious petitioners, who afterwards are left to complain that after having performed successful rituals that achieved results, the clients were still unhappy because some element didn’t play out according to expectations — the spell worked but didn’t happen as fast as they wanted, or they got more money/love/success but not as much more as they wanted. We must remember that magic is considered to be scientifically unproven. One reason it is bestowed with this status is because we cannot really view the alternate timeline wherein the spell wasn’t cast — which is just about the only way we would be able to prove what the magic did or didn’t do. If a man casts a good luck spell, and two weeks later his car breaks down, does that mean the spell failed? Or might it be that the car’s being in the shop saved him from a worse misfortune, like a serious accident, and consequently it is good luck that his car was in the shop? There’s no way to compare situations to see the “what if.”
Spells meant to influence someone else can be even harder to judge, since we might not be privy to all changes in the subject’s behavior. It is even possible that we might see only behavior that seems opposite of what we wanted, and so we would assume failure of a spell that actually had been a success. For example: I knew a woman who had a love spell put on her by a man that she hated. She hated every moment she spent with him, but when they were apart she couldn’t seem to get him off her mind, and always was willing and anxious to see him again. She eventually figured out that he’d put a spell on her, and she took steps to remove the magic. After that, she didn’t speak to him anymore. The man might well have assumed that his spell didn’t work, since all he would have observed was a woman who could barely stand him and who ultimately severed all contact with him. He wouldn’t have known just how well his magic worked.
The point of all this is a reminder to keep reasonable expectations when it comes to the practice of magic. It’s not a practice that’s about a lot of concrete Yes and No information. It’s more art than science, and many of its powers remain mysterious due to their blurring of all that which is natural. Success is subjective. In effect, any time a person wants a spell to gain “more” of something, it is impossible to promise how much “more” one will get. One can always have “more” and still find it lacking. With magic, even when we get what we want… we may find that we want it again.