Have you ever noticed your dog DOESN'T chase the mailbox but he DOES chase squirrels?
Every thought about how your dog does not sit in front of the fridge and BEG for food even though he KNOWS that is where the food lives?
Why? Because dogs do behavior that works. Only. Always. ALL THE TIME. It's evolution guys, it is wasteful to spend energy you don't have to - in "the wild" this could mean death, so living organisms have developed the ability to fade out behaviors that don't "work" and rely on those that do.
Mailboxes don't run, it doesn't work to chase them. Squirrels do. Do what works.
The fridge may be full of food but it is impervious to sad puppy dog eyes, you know who isn't? Most every human on earth. So dogs beg from people!
Here is what the SCIENCE of behavior tells us:
----> If a behavior persists and repeats it is because it WORKS for the dog. It serves a purpose. It is REWARDED, or REWARDING. Period. If it didn't, they WOULD NOT DO IT. <-----
Are there exceptions to this? Sure! But there is usually an underlying pathology there, a dog with cognitive issues such as an ailing senior, or dogs who have experienced trauma severe enough that it has mutated the way they learn. But in 99.9% of cases, it is true.
If there is a behavior you DON'T like - the first step is to figure out how it is working, so you can stop it! What does the dog get out of it, what is the reward? Does your dog end up with attention - in the form of people talking to him, laughing at his antics, or even angrily chasing him around the house? Does your dog end up self rewarded - does he end up accessing something he enjoys playing with or chewing on? Or is it self-rewarding in and of itself - does he just LOVE the act of CHASING?