On the Difference Between Sin and the Cafeteria
Matthew Archbold distinguishes between being a sinner and being a cafeteria Catholic:
... We all sin. But that doesn't make us cafeteria Catholics. The real difference is that cafeteria Catholics simply don't acknowledge sin.
While we all transgress, a committed Catholic will still judge themselves against an established standard. We will inevitably fall short of those standards but we still strive to achieve it and emulate ourselves after Christ to the best of our ability.
The cafeteria Catholic may act in very much the same manner as a faithful Catholic but simply removes all that striving. When confronted with a discrepancy between their will and the teachings of the Church they simply change the standards based on what they feel is right for them. And let's face it, when we set our own fungible standards, sin becomes impossible because our decision making becomes the standard of behavior.
We all fall short of the standard. The cafeteria catholic just lowers the standard.