I just use gmail to send and receive messages. Do I care if google reads my messages? A little bit, but not too much. I doubt a google engineer is sifting through my account reading my messages and getting jollies out of it. What I don't want is some sort of algorithm or third party to run against every email message I've sent in order to build a hidden profile on me and my habits and use that to target me in some way.
In my experience, email is a double edged sword. It's a great way to communicate, but it's also a source for bad productivity if you're not careful. If you're using a client like Outlook to manage your email, you'll get a notification each time an email comes in. The notification is a distraction and the temptation is to stop whatever you're doing and see what the message is. If you get an email every 15 minutes, you'll never get any work done. I usually check my messages about twice a day and call it good (though I rarely get any, so who cares?).
It also takes a long time to write up a reply for an email. Writing is slow. Time is money. When you're responding to an email, its worth taking a moment to think about it: If you're responding to just one person in the office, it might be faster and more efficient to just respond verbally instead of playing email pong. If you need to broadcast a message to many people, it's probably faster and more efficient to email.
Personally, I hate communicating with people via technology. It's a poor proxy for genuine human interaction, which I don't think we get enough of these days. face to face > phone call > email > Instant message