In English the preposition used with a word can change it's meaning. mad at you - angry with you (negative) mad about you - thinks that person is amazing to to point of being crazy (very positive) I have never heard "mad on you" When using the word mad remember that in American English it tends to mean angry where as in British English it tends to mean insane. I hope this helps!

Mad on you = incorrect and just about never heard. Mad at you = Angry at you. You could also say "angry with you". There is no reason why they can use different prepositions, it's just the way the language developed. Mad about you = I'm very much love with you. (idiom)

Thanks, good question! I could understand and remember about them with your question ^^