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Hugging
There aren't too many people who don't enjoy hugging their dogs. However, there are quite a few dogs that hate it when you hug them. In the wild, hugging, or rather one dog placing his paw on another dog's back, is a way of establishing dominance. When you hug your dog, he may feel threatened or challenged.
Walking Without Exploring
Rainy or cold days are the worst for letting your dog do what comes naturally. You don't want to be stuck outside for what seems like hours while your dog sniffs every tree, fire hydrant, and piece of grass he can find. Dogs hate not being able to sniff because smelling an object is how they learn and 'see.' Even if you let your dog sniff for a couple of minutes, you'll be doing him a huge favor.
Teasing
Typically, children are guiltier of teasing dogs than adults, but plenty of grown-ups think it's funny. Teasing by barking at a barking dog or pulling a dog's tail not only upsets the dog, it shows the world how immature a person truly is.
Being Lazy
Dogs, like people need stimulation. They hate lying around waiting for something to happen. Dogs need to be mentally and physically stimulated for them to be happy and stay out of trouble.
Patting
Imagine how you would feel is someone came up to you and began to pet your face and head. Most dogs tolerate this type of behavior, but that doesn't mean they like it. Dogs, like people, need their personal space.
Dressing Up Your Dog
Most dogs do not like playing dress-up. They will sometimes tolerate getting stuffed into a silly costume, but the concept still isn't really a thing to them. They just understand that their movement and vision is often constricted while wearing the costume. If you dress your dog up, take a quick picture and monitor the dog to see his or her reaction. Take the costume off if your dog seems uncomfortable.
Leaving Them Home Alone
Dogs are pack animals and want a leader. When they are left home alone, some dogs act out because of their anxiety. Certain breeds like Labradors, Retrievers, and Terriers are often more affected by being left alone, although any dog can suffer from separation anxiety. Make sure you have a routine that you can stick to so your pet understands when you will leave and come home.
Looking a Dog in the Eye
Although this rule applies to some pets, it is really for those folks who approach a strange dog while looking him in the eye. In the wild, dogs challenge one another by staring each other in the eye. For your own safety, never approach a dog while you're staring at it.
Too Much Baby Talk
Dogs do not understand our language except for key words and phrases they're able to associate the sound with a specific action or response. If you baby talk your dog too much, the mumbled phrases you're saying to them just won't be comprehend. You could possibly run into a situation where your dog ignores you all together.
(Answers.com)