We have 1 client that refuses to put a title in every email she sends.

It is very annoying that you have to open every email to know what the email is about.

How hard can it be to add a title because she always write a book in the email.

Welcome to devRant. Sounds like a real pain.

there was a programmer here who wrote a Outlook plugin in order to categorize the importance of his email. A slackbot notified him when he recieved some important emails.

Start with waiting a day or so before responding and the inform them that your third party spam filter always quarantines their emails and you only learn about them when you get the daily report.

Then its not your fault

Start charging for searching time

This is why google inbox is great. It automatically sorts through everything and displays it based on content. A bunch of github merge notifications? It'll bundle them together and give me the title "5 merge notifications from github.com/ironman5366/..." A bunch of emails from one person? It'll say "20 emails from Whoever, summary of email1, summary of email2..."

Well, we have a client who write down every fucking details in subject column. He left body field empty. No need to open email at all, except some times. But this annoy me. I think we annoyed by everything which is not in standard order.