How do you know if you're a "carnal (i.e. immature/driven by the flesh) Christian?"
1) You struggle with envy or jealousy. You're never content with what God has given you. You must always have the latest and greatest "whatever" that everyone else has, or you're not happy. You must be the center of attention. It bothers you when anyone besides yourself (or your family) receives praise/recognition.
2) Strife follows you. You're always fussing with someone. There is always someone you're mad at (or vice versa), usually over petty things that have no eternal significance. Every day of your life is a soap opera. You live for drama.
3) You promote division rather than unity. This is often done under the guise of holiness, when it's really about personal preference. To you, there is no such thing as a secondary issue. Every issue is of primary importance, and everything is black and white. People are either for you, or against you. Those that are "against" you (or don't feel the need to pick a side) are quickly labeled and demonized. You need a battle to fight, and a side to take, to feel good about yourself.