Why does my dad never approve of my actions?

Ok I'm 19 I'm an honors student at college I got a 4.0 in highschool and am on the Deans list in my college an yet EVERYTHING I do my dad criticizes me. I mean I am like an exact copy of him: I play tons of instruments, we like the same music, I share his sense of humor, etc. But when it comes to work and school he is constantly putting me down and saying I have no work ethic. I mean I'm doing way better than he was in school so you would think he would be proud of what I've done but I catch him sneaking behind my back telling my mom that Im lazy. I know he just wants the best for me but with my talent and intelligence I should be able to be fine idk why he's always on my back. I always tell myself I don't need his approval but it's so frustrating. I went to school for engineering and dropped to nursing and he's saying I'm wasting my whole life. Meanwhile I'm focusing on my art/music, which he has STRICTLY encouraged my entire life, and yet he now tells me I'll never be a rockstar...