In the flashback to Christmas 1995, Pussy misses the sitdown between Jackie Aprile and Junior which he himself brokered because of his comare's mother having a stroke. This was meant to illustrate to Tony and Silvio that he must have flipped then (though we know he wasn't flipped until 1998).

But shouldn't missing a high-level sitdown, for any reason, merit a death sentence? It shows that you have put something above La Cosa Nostra.