If someone is emailing me due to something I messed up on, it's important. If replying means I can close a sale, it's important. If not replying means I can los

If someone is emailing me due to something I messed up on, it's important. If replying means I can close a sale, it's important. If not replying means I can lose a customer, it's important. If I am blocking someone's progress by not replying, it's maybe important. And my favorite unimportant email: anyone asking me to update them on the status of something.