I REALLY REALLY appreciate everyone's replies.
I rode again today with my friend. Blu consistantly ignored my asking so I had to command what I wanted at times. He was being high-headed and "spazzing" on the ride back home. He was just excited I guess. But that gives him no reason not to let me get on.
I really don't think its a tack issue. My uncled tried to say its his grain but I know for a fact its not. I'm just so hurt and frustrated.