It might be more that I just generally found it to be a bit overrated and fairly boring. Like, I give it a 7 or an 8, which means I still enjoyed it.. but just not to the level that others did. I know that it's based loosely on a book, and that means they are limited with what they can do with it. But no real suspense for me, not enough plot. It was: Kid gets pulled into crime family. grows up to do some heists, gets caught up in the life, gets in trouble, goes into Witness protection. End movie. No real twists and turns. No great screenplay/dialogue except from Liotta.
Also kind of felt the other characters were underused, which again, kind of is because this is a pseudo-autobiography and Ray Liotta's character gets most of the screentime and line delivery. But when I look at the movie Heat, there is no scene in Goodfellas that compares to the Diner scene with Pacino and Deniro. There is nothing in Goodfellas that was ever really eye-popping for me. Glamours mob life, a few guys get killed, roll credits.
However, one thing I do like, it draws you in from start to finish. It's an easy watch in that regards. You could put it on in the background and jump in and out as you please, because there's always something happening.
I'd also like to add True Romance to my list of "mob" movies.