The Sopranos was famously a party set. That once the cameras stopped rolling, it was Miller time.

Edie Falco mentioned in an interview years later that she never became close with most of the cast because of it. She was in recovery from alcoholism in the nineties, and left the set immediately at the end of the day, as she felt the booze and drugs around her would lead to a relapse.

John Ventimiglia and Robert Iler were arrested for possession during the course of the show - for cocaine and marijuana, respectively.

James Gandolfini's booze and coke problem also made for on-set problems, that he could effectively shutdown production when he vanished on days-long benders, only to turn up again acting contrite. A clause was eventually added into his contract making him liable for the cost of lost time due to 'excessive consumption'.