Inzaghi is pretty much hated wherever he goes.
In Atlanta he manged to have a spat with then a wonderkid and Atlanta hero Morfeo.
By the way, Carla admitted that one time Del Piero and Pippo had to be separated in the locker because they were arguing too much.
Also, Del Piero and Pippo never celebrated other's goal in their last season together.
I personally it developed when Pippo and Del Piero were arguing about who was going to take the penalty against Sweden in International friendly.
Considering the circumstances, I think it is Pippo's fault. Del Piero were having a serious goal drought and lack of confidence. And Pippo were taking all the chances. Talking about selfishness, I never seen more selfish player than Inzaghi. Also, I must disagree with Erik that Del Piero is selfish. If you look at Alex whenever Di Vaio scores, he looks just as happy as the goalscorer himself. I think it was just the fact, Del Piero didn't like Pippo. After all, do you want to see Pippo's annoying goal celebration and lack of acknowledgement of his teamate.

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Nevertheless, seeing Pippo being more respectful towards his Rossineri teammates, I think he has matured a bit. And so have Alex.