It's important for the actual day-to-day work to fit your personality/interest/aptitude. People sometimes confuse "doing what you love" with "doing what you care about". The actual subject matter of your work can be mundane as long as you enjoy the kind of problem-solving that this job requires.
For example, if you work in sales you shouldn't need to be selling solar panels for your job to be rewarding. The process of interfacing with other people and finding a way to match that person's needs with a product is what gets sales persons out of bed in the morning. It's the process that they find exciting.
Here's another example. My wife became a veterinarian because she has cared about animals as long as she can remember. But when she finally got a job she realized that being a veterinarian doesn't mean you get to spend quality time with animals. Most of the animals she sees aren't happy to be there and she has the scratches to prove it. Really, most of her day is spent interfacing with clients (dog/cat owners), diagnosing illnesses, euthanizing or treating wounds, filling out paperwork, etc.
So when you're evaluating careers, pay attention to the day-to-day work. This is why internships are so helpful. Take that opportunity to see what these people actually spend their time on...