Why am I prompted to answer security questions after I logged in with Apple ID? It makes me frustrated to go to search and find the correct answers.

There are many cases where Apple will ask you to answer security questions were saved in your Apple account. For example:

1. Example 1 - Assume that you haven't logged in to your Apple ID account for a long time. If you try to log in to your apple ID account at https://appleid.apple.com/, you will be asked to answer your security questions right after you entered your password.

You are frustrated because you think that you password is good enough to allow you to login. But Apples does not think so. Apple wants to double check your identity if you have not used accessed your account for a while.

2. Example 2 - Assume that you have logged in successfully. If you go to your profile and try to change your password, you will be asked to answer your security questions before Apple displays the change password screen.

You are frustrated because you think that you should be allowed to do any thing in your profile. But Apples does not think so. Apple wants to double check your identity if you are trying to change security related settings.

The picture below shows you the "Email Preference" section of your Apple ID profile:

⇒ What Are Apple ID Security Questions

⇐ Managing Apple ID Profile

⇑ Getting and Managing Apple ID

⇑⇑ Apple iPhone - Frequently Asked Questions