Why does he have to be humble ? I wasn't aware of that being a prerequisite to greatness
I never said anything of the sort. What I was alluding to was that a lot of people (including myself) prefer players with a positive persona which helps us to get behind and support that player.
Why do you think Tomic is one of the most hated youngsters out there? Most people need good tennis + good personality before they are willing to support that player. Being humble is a positive trait, arrogance isn't. You could be the best player in the world, but if you're a complete wanker then far fewer people care.
How this is relevant to the OP is that I don't think Tomic will become a top 10 player as early as next year because mentally he needs to mature. His ego is up in the clouds, not surprisingly clouding his judgement. He's too young emotionally... selling his fluro orange Beemer isn't enough. Tough talking teenager is just that... talk.