I think much of Tony's dislike of Bobby stems from Tony seeing Bobby as the man Tony could never be. For example, Bobby had a stable,happy marriage to Karen. Even the other wives were moved by his devotion to her and the fact that he was one of the rare guys who didn't have a mistress.Bobby also was respected by Junior,who liked to remind Tony of his shortcomings both as an athlete and a nephew.Bobby seemed to be one of the few "inner circle" guys who wasn't in some way warped.Chris had the drug and inferiority drama,and Paulie was pretty much just plain (wal)nuts.Bobby was a low maintenance,laid back guy who did as he was told,carved out a niche,made a good living,and struck me as a man with a great deal of inner peace and personal happiness.Tony always seemed to have a "why me" attitude and I think that he looked at Bobby as a guy who just fell into a relatively happy life,as opposed to being a fundamentally decent guy who deserved his life.