Jumping
We often pet small dogs or puppies when they jump up at us for attention. This is not so cute when they are wet or dirty, or when they grow up and weigh 80 pounds. They can knock smaller people over, hurt smaller pets or people. Jumpers can knock food or drinks over, and causes humans to react poorly. If your dog jumps or paws another dog that has a dominant personality it could trigger a fight. Ignore or discourage jumping 100% of the time, encourage and reward sitting for your attention, because that's all they want!

Shake a paw
This is the most common 'trick' people teach their pets, but it can lead to serious behavior issues or injury. They learn that this behavior is accepted and encouraged, so soon they start to do it on their own. A misfired paw can scratch skin, or even a child's face. They start to paw for attention or food and can become demanding and dominant.

Fetch
The first thing everyone wants to do when they play with a dog, is throw them a toy to fetch. This can be a great game, if your dog is already well socialized, exercised and obedient and they have earned the right to play a short game. Problems arise when the only outlet for a dog is a highly intense game of fetch. You get home after a long day, and take the dog out for an exciting game of fetch to tire them out. Over time the dog becomes overly excited to the point of obsession. Many dogs show no interest in normal doggie activities, and many become possessive and aggressive over the ball. To tire your dog, work out their mind, with some obedience or tricks instead of increasing their stamina. You did want a tired dog after all.