#1 Not enough exercise!
Think of a 5 year old child cooped up in a house or backyard day after day, week after week. It gets boring and is unhealthy for your dog both mentally and physically. Dogs need to get out and explore new things and most importantly they need to bond with their owners! Just as kids need bonding time with their parents with playtime and exploring the world, so do dogs.
#2 Taking your dogs food and toys away.
People do this to show who is alpha, but this is unnecessary. All dogs that have been raised with boundaries will willingly share their food and toys with you. If you take your dogs food away constantly they just see you as being a mean bully. Your dog doesn't understand why you are taking their food away and they can actually become aggressive by you doing this.
#3 Crating your dog for punishment.
Crates should be used for training yes.. but the idea of that is to make it a fun and safe place of comfort. Putting a dog in their crate as punishment will do the opposite and they will associate the crate with negativity. Dogs don't understand time out for punishment like humans do, they just know negative reactions in the moment of the action. Just like if a shock collar shocked a dog a whole minute after the bark they would not associate the shock with the bad behavior, it has to be instant and done with.
#4 Constantly yelling at your dog.
"Imagine if the only training you got at a brand new job was your boss yelling at you constantly for your mistakes." This is enough to make you hate going to work! Training does not mean yelling only when the dog is doing something wrong. You have to ask for the behavior you want, be consistent till the desired action, then praise them like crazy! Make them eager to please you with positive reinforcement and they will know what to do no yelling needed.
5# Leaving your dog alone for extended periods of time.
If you work a 40 hour week and travel a lot a dog is not a smart choice for you. Dogs are social animals with the need for attention and bonding, they like to spend time with you as much as possible! If they don't get that they get depressed and stressed which often leads to destruction. It's very important to make time to exercise and play with your dog.