Going for the Money, Honey: Bringing home a paycheck is important, but the size of it isn't actually a great predictor of job satisfaction. In other words, you can make six figures, but if you hate what you're doing, you'll find it hard to enjoy the fruits of your labour. Look for a balance between making enough money to support yourself and work that fulfills you.
Ignoring Who You Are: Your personality type, interests, values and aptitude make you better suited for some occupations than others. These traits are intrinsic, which means you can't change them. If you don't take them into account when selecting a career, there is an excellent chance you will wind up in an occupation that is unsuitable for you.