interesting question. magic really is intent, it's a neutral force that we make positive or negative. i do agree manipulating a person to love you or do something for you is bad. health spells work similar, you think you're doing good by helping a loved one, but maybe they didn't want you to cast a spell on them because they think it's bad, once again, you've done what you wanted and not them, so it's negative. you need to reflect and think about it before ever casting.
what would make a spell positive and not manipulative is if you cast, say a love spell, asking for new love to find you. you don't have anyone in mind, but you are already destined to meet this person, so you're speeding it up.
i don't want to say magic is pure manipulation, i look at it as more you pushing fate a bit faster in a direction. we walk a winding path full of forks, magic can very quickly change our path. let's say you healed your friend, but you did it without their permission, your positive spell would be more negative because you're imposing your will onto them. as a result you get sick [call it karma] you can't go to this concert [example] you were planning on going to, so you give up your ticket to your friend who meets someone at the concert [who fate had you to meet, but since you meddled, you changed your fate] and they [your friend and the person] begin dating. fate has a way of evening things out in my opinion at least. hope that explained things and didn't just confuse lol.
you should meditate on your feelings, see if the answers come to you. magic isn't something to play with, so it's very wise to be asking questions. myself, i only cast when things get really bad for me. there have been times where i've wanted to cast in the heat of the moment, but i choose to wait a few days to think about it. i have a few spells that call for casting at very specific times. [like a saturday 3 days after a full moon]