10. Neil McCauley - Heat
The Rule: "Don't let yourself get attached to anything you are not willing to walk out on in 30 seconds flat if you feel the heat around the corner."
Michael Mann's masterful crime thriller Heat sees bank robber protagonist Neil McCauley (Robert De Niro) live by this single rule, to not be weighed down by anything that might impede a quick getaway if necessary.
Except, McCauley ultimately betrays his very own maxim at the end of the movie. As he heads to the airport to flee with his haul, he learns of turncoat Waingro's (Kevin Gage) location and instead decides to seek revenge on him.
Though McCauley does indeed kill Waingro, but also ends up chased by LAPD Lieutenant Hanna (Al Pacino), who guns him down before he can resume his escape.
That's some delicious dramatic irony right there - despite his own preaching throughout the movie, McCauley couldn't let go of his own emotional baggage and paid a deathly price for it.