I think some people just struggle to see the difference between arrogance and confidence. An arrogant driver would never get anywhere, they would not be able to take advice/criticism from their team engineers and the driving will suffer big time as a result (seen it happen numerous times). Confidence on the other hand is vital, if you dont beleive you can win then your not going to have much chance of winning!
I think the reason why the 'lesser' drivers (i.e. not currently as succesful as the top guys) like Kubica appear to take the success in a different way is because a) they arent really used to it yet and b) most of the time the result comes as a suprise to them and the team! Guys like Lewis/Kimi/Massa are all expected to win by their teams, this is why the confidence is so vital. Kubica/Piquet (etc..) are expected to score some points, anything else they do is a bonus.