Stress
Invest in herbal tea, Feng Shui, your home, and go for weekly massages. You will be working all hours, pecking through loads of clues, and chasing tons of dead ends. It's enough to make the average citizen go mad. But that's not you.
You'll learn early on that not every case will be solved. The sooner you can accept that, the less tense you'll be. Don't be afraid to punch a heavy bag occasionally. Whatever your outlet, make sure you process your stress in a healthy way. No smoking, drinking or stress-eating. Those are very bad, mm-kay?