1. Cats do what they want, when they want
2. They rarely listen to you
3. They're totally unpredictable
4. They whine when they are not happy
5. When you want to play they want to be alone
6. When you want to be alone, they want to play
7. They expect you to cater to their every whim
8. They're moody
9. They leave hair everywhere
10. They drive you nuts

Conclusion: They're like little, tiny women in cheap fur coats.