Not that long ago, the Iwata-san book was released, which chronicled the work and life of Satoru Iwata. Included in that book was an interview with Masahiro Sakurai, and now the first part of that interview has been posted online for free. We have a breakdown of what was said, thanks to PushDustIn.
Sakurai recalls being interviewed by Iwata back when he was just 18 years old. Sakurai looks back on the interview fondly, remembering Iwata's smile, and how closely Iwata paid attention to what was being said. Iwata was apparently taking notes on Sakurai's interview the entire time.
Not surprisingly, Sakurai says that when issues popped up during game development, Iwata was quick to hop in and help set things right. Iwata did this during Melee's creation, and did so without even being asked to come in and help.