If you answer “yes” to something you are answering in the affirmative.
If someone answers “no” to your request then no means no. This has been a public service announcement.
An affirmative response doesn’t have to be an outright “yes.” It can be a statement supporting what someone else said.
You might provide an affirmative response might to give positive feedback and a boost of confidence to someone. Then again, you might say it primarily to get someone off your back and avoid an annoying argument with a whiny, little insecure individual. The world isn’t always a pleasant place. Without becoming too unethical, you have to do what you have to do to thrive and survive in it. Please answer in the affirmative if you agree.