Rob Allen, an active member of the Zend Framework community, makes the case for giving some love to API errors.

It's not hard to have great error responses; you just need to care. Poor error response cause developers to give up with an API and go elsewhere, so it's a competitive advantage to get this right. Developers integrating with your API will thank you.

https://akrabat.com/api-errors-are-first-class-citizens