Love spells are the most tricky spells when it comes to casting. I believe more people have had miss spells or backfires with love related spells more than any other.
Are they a waste of time? I don't believe so. Do I do love spells? Not anymore but if the right reason came about I would.
You can not make someone fall in love with anyone else. All you can do is strengthen the chemistry that is already there. Be careful though this is what gets most people in to trouble. It can cause a person to go insane with their emotions. You may have a person who can't stop thinking about the other person and this can lead to trouble. Sometimes it allows the person to see the other person for who they really are and that love turns to hate. I suggest if you want to go forth in casting a love spell you remember to be specific in what you are looking for and even say what you do not want to happen. Just remember the gods love to find loop holes in what you ask for and they do have a scene of humor.