Writing, acting, direction---this is hands-down the best buddy movie ever made. For the life of me, I don't understand why it's not more popular or better known!
The plot flies. It's hilarious and poignant, full of wonderful little touches and unforgettable performances (Dennis Farina is a mob boss who threatens his employees with lines like "you and that other dummy better start getting more personally involved in your work, or I'm gonna stab you through the heart with a f--king pencil").
And the ending is unbelievably satisfying. A great guy flick, and my top "sleeper" hit of all time.