This week Google officially shut down Inbox. The app was a straightforward, effective email management tool. Its simplicity is what made it great. The sunset was announced a while back, but I discovered the shutdown while I was on the road - trying to access my email. Oops.

Having no email access, however, turned into some great productivity. I stumbled upon a secret some of the most productive entrepreneurs know.

No email on your phone

It's sounds reckless: Removing email from your phone. Some of the most successful entrepreneurs I know rarely check their email on their device or, on the extreme end, drop the email app altogether.

This isn't as rare as it seems: Arianna Huffington, Marc Benioff and others make a point to put their phones "to bed". Unplugging gives you the opportunity to be more present personally and professionally.

One successful entrepreneur had a situation similar to mine - and decided not to add the email app back to their phone. Years later, they still don't have phone email access! They told me their productivity skyrocketed afterwards.

Why you become more productive

I just lost email access this week, but I can already feel the effects.

First, I caught myself grabbing my phone and tapping where the email app used to be from pure muscle memory.  This was at random times, like when I was cooking dinner or waiting in a line or sitting quietly by myself. I didn't realize how trained I was to mindlessly check my email. I can now redirect myself to do something else, to be thoughtful.

Second, it forced me to let go of what I couldn't control. I've been putting out a lot of fires this week, but most of the elements I haven't been guiding. In short, there's been a lot of creating and waiting. It happens. If I had email access, though, then it would be much easier to check it every other minute. Instead, I had to go to my office, wake up the computer and log into my email. In a very Stoic sense, it forced me to be present, trust the timing of things, and to be fully present and take full responsibility for what I did control.

Lastly, I needed the phone less. I already took off the Facebook app, only access Twitter through the website and keep my notifications off for Instagram. What did I need to grab my phone for?

The focus became writing down my business strategies, being more present for my family and, most importantly, cooling my obsession with checking on responses. Email puts you in reaction mode. Success comes from initiating. The best entrepreneurs I know put this into practice, and removing your email app is a good start.