At times you may prefer not to answer the phone, but you may not want to miss an important call. Say What is a free Android app, which discloses the reason for a call before picking up.
Know the reason for a call without answering the call.
How does Say What work?
By downloading Say What to your smartphone you can add a "subject" (like you would in an email) to the calls you make. The recipient of your call will know why you are calling. It works even if your contacts do not have the application installed.
Also, if the call recipient has the app installed, you can send a message in response easily. Say What provides several predefined messages and emoticons organized into categories.
Download Say What free for Android and make your reason for calling known to your more demanding contacts.