• Both take up too much space on the bed.
• Both have irrational fears about vacuum cleaners.
• Both are threatened by their own kind.
• Both mark their territory.
• Both are suspicious of the postman.
• Both are bad at asking you questions.
• Both pass gas shamelessly.
• Both like dominance games.
• Both tend to smell riper with age.
• Neither of them tells you what's bothering them.
• Neither of them does dishes.
• Neither of them notice when you get your hair cut.
• Neither knows how to talk on the telephone.
• Neither understands what you see in cats.
• The smaller ones tend to be more nervous.