They do not have the intelligence level that you do so they may not always know what you want...some understand human language better than others, collies for example are extremely smart. Others really respond to tone and inflection...they get yelling but not sit...soemtimes they will try a few things to see what you want. Personally, I have my pets just to pet and enjoy in a naturalistic sense not becuase of their training ability.

So basically would you yell at a baby that pooped in it's diaper or would you understand that it just wasn't capable of using the toilet yet but one day it would be. If someone were not as smart as you would you expect them to be able to do everything you would. If you make a mistake how would you feel if someone yelled at you rather than simply correcting your error.

Is your dog upset because you have not learned how to bark yet?