Patrick writes on the signs that you are legalist. For me, his last point hit home:
Pride and legalism can even take the form (but not the essence) of humility and piety. How do you react to your own sin? Do you run to God while the blood is still dripping from your hands? Or do you engage in various forms of penance such as self-loathing, making promises, and engaging in extra work to make up for your sin?