Living with terrible housemates could be a nightmare! But, lucky for you, these tips would save you from any passive-aggressive behaviour of your housemate from hell.
1- Ignore their notes
If your housemates leave hostile notes around, DO NOT write back. Ignore the notes or confront them directly. That would nip the problem in the bud.
2- Don't get yourself into debt
Make sure to not mix up your expenses. Never ask them to pay for you and vice versa. Also, never leave any debt for years before asking them to pay you back.
3- Don't steal back
The worst kind of housemates are the ones who constantly 'borrow' (read: steal) stuff from you. Obviously, it's difficult to catch them in the act sometimes. However, do not label too much of your stuff. That doesn't help much, unfortunately.
4- Have clear-cut boundaries
Assign separate cupboards, or set shelves in the fridge to each housemate. If you find your belongings missing, do not accuse anyone. Instead, ask a general question, such as "Has anyone seen my lip gloss?"
5- Laugh at them
Only resort to this in face of a raging housemate. When someone is really angry at you, you best respond with a laugh in their face. Save any nasty remarks, and just laugh!
So, there you go! May these top tips help rescue you from that pain-in-the-neck housemate.