Both take up too much space on the bed.

 Both have irrational fears about vacuum cleaning.

 Both mark their territory.

 Neither tells you what's bothering them.

 The smaller ones tend to be more nervous.

 Both have an inordinate fascination with women's crotches.

 Neither does any dishes.

 Both fart shamelessly and don't understand why it is disgusting.

 Neither of them notice when you get your hair cut.

 Both are suspicious of the postman.

 Neither understands what you see in cats.

 Dogs do not have problems expressing affection in public.

 Dogs miss you when you're gone.

 Dogs feel guilty when they've done something wrong.

 Dogs admit when they're jealous.

 Dogs are very direct about wanting to go out.

 Dogs do not play games with you- - except fetch (and they never laugh at how you throw.)

 You can train a dog.

 Dogs are easy to buy for.

 The worst social disease you can get from dogs is fleas. (**OK, the worst disease you can get from them is rabies, but there's a vaccine for it and you can kill the one that gives it to you).

 Dogs understand what "no" means.

 Dogs mean it when they kiss you.

 A dog's parents will never visit you.

 A dog loves you when you leave your clothes on the floor.

 A dog limits its time in the bathroom to a quick drink.

 A dog never expects you to telephone.

 A dog will not get mad at you if you forget its birthday.

 A dog does not care about the previous dogs in your life.

 A dog does not get mad at you if you pet another dog.

 A dog never expects flowers on Valentine's Day.

 The later you are, the happier a dog is to see you.

 A dog does not shop.