Dear 100 Hour Board,
I want to end my smartphone addiction. However, I'd still like to be able to email from my phone. Is there a phone out there that texts, calls, and emails with ease, and that's it?
-My Neck Hurts
As Spectre points out below, feature phones (aka "dumb phones") can check email, and they come in several form factors that you can choose from. However, they can also access the internet if you try hard enough, which sometimes isn't very hard. I have a friend with an addictive personality who has tried in the past to overcome certain addictions by switching back to a feature phone, but it didn't turn out great. Werf eventually figured out how to access the internet through werf's feature phone, and it actually cost more money than if werf had been on a smartphone plan.
My recommendation would be to take your current phone and uninstall/disable any and all apps that you feel like are contributing to your smartphone addiction (including and especially any browsers, and even Google search), then put in a parental lock on installing/enabling any apps. If you feel it is necessary, you can have someone you trust (like a roommate or family member) lock them behind a password so that you can't change your settings back whenever you're bored.
Dear Rubber Necker,
If you are willing to compromise a little, you can get The Light Phone which will actually work with your current smartphone. Basically, it's a small, touch-screen phone that connects to your current smartphone for calling so you can leave your smartphone home and just take this little guy. You would just need to let your friends and family know that you won't text or email back as often and just check your texts and emails on your regular phone back at home. This may not be the answer you are looking for but it's an option.