Being locked out of your car is not an interesting problem. Call five locksmiths, hire the cheap and fast one, you'll be fine.
And getting a script written or a book cover designed isn't that interesting either. There are thousands of trained professionals happy to do it for you.
On the other hand, if you need a script that will win awards, sell tickets and change lives, that's difficult. And interesting. Or if you need a book cover that will leap off the shelf, define a segment, make a career—that's hard as well.
An interesting problem is one that's never been solved in quite this way before. It's not always going to work. The stakes are high. It involves coloring outside the lines.
Most solution providers (freelancers/firms/professionals) shy away from the interesting problems. There's not a lot of firm ground to stand on. There's more apparent risk than most people are comfortable with. It's too easy to shy away and pull back a little.
And it's a big but…
The few who are willing to engage in interesting problems are worth working with.