I think if we can all agree to these five rules of thumb, everything (or at the very least my life) will be better.

If the phone cuts out, whoever made the call that dropped out is the person who calls back. Let’s not spend 5 minutes both calling each other at the same time and not getting through. Then waiting the same amount of time to let the other person call.
When there is an email introduction, BCC the person who introduces you. It goes like this: “Thanks for the introduction Jane (moved to BCC), great to meet you Henry.” That way Jane doesn’t have to be included in the next 7 emails when we set up when and how we’re going to catch up.
If a coffee or lunch meeting is part of a program you are delivering, or you're selling or promoting something, or they travelled to you, or you’re in any doubt, you pay. It’s good manners and good business.
Don’t write something about someone else you wouldn’t be OK with them reading. It’s a better way to live … and one day you’re going to make a mistake and send the email or text to the wrong person (like I did last week) and they will read it.
Start and finish meetings (and programs) on time. Finishing early is OK too.