What might be considered taking liberties in one culture may not be the same in another. Inviting yourself to a party might not be taking liberties in some cultures.
Pro Tip 2/3
Personal Boundaries
Taking liberties often involves crossing personal boundaries one should respect. Reading someone's diary without permission is taking liberties with their privacy.
Pro Tip 3/3
Implicit Permission
Sometimes, an action can be considered taking liberties if implied consent isn't clear. Borrowing a book without asking could be seen as taking liberties.