I don't like the way that many seem to be using anything they can to degrade Messi. Right, he may not be the perfect being, but nobody is. The fact is that in comparison to many footballers nowadays, and many of the others who are considered as the greatest, he is quite humble.
Perhaps he has taken the odd dive, perhaps he has been slightly sulky when not everything has gone the way he wants it to, but those dives are few and far between, and he generally always gets on with stuff. I've never really seen him sulk at all: certainly not on the pitch.