9.9/10 stinky bananas
A damn near perfect movie in my book. The three headed monster that is Scorsese/De Niro/ Pesci hit the nail on the head with this mafia movie. Each of them giving career best performances. Plus a young Ray Liotta, before he became the ugliest looking guy in Hollywood. All of the Chantix in the world couldn't save him from being a repulsive human.
Goodfellas is comprised of iconic scene after iconic scene. From the restaurant scene to the prison scene to every scene where Pesci loses his shit on someone. Non-stop action and excitement from start to finish.
In terms of best mafia movie of all time, Goodfellas is far and away the best. There are many Godfather stans out there, but to them I would say that you're wrong.