Yeh totally agree! I love the chat windows but its annoying when they pop up automatically.. That is just poor design.
The worst is WPEngine. I already pay for their service, but whenever I look at an article on "How to do X", I hear beep!, and there's a sales chatbox in the corner.
I've taken to starting a chat, letting them know their site is annoying and I'll never use it again, and then closing the page.