From my dad, I have also heard similar statements. When I was little, it always seemed so ambiguous, and if anything always put me under the impression that there was something my father wasn't telling me, when in reality he's just really bad at communication, but regardless, he has always wanted the best for me. Now that I am in university, I finally understand what he has meant by saying "You have to do better than me, don't be me". I completely understand my dad in the sense of why he doesn't want me to be like him, he doesn't want me to live a sad reality the way he does, and while it may sound like I am taking pity on him, I am not. I just understand he has a lot of reasons as to why he can't be successful the way he wants me to, but if anything it has always encouraged me to do better for my family as a whole.