This observation from The Verge's Ellis Hamburger:

Let's face it: we're all pretty horrible at turning off push notifications on our smartphones. You install an app, give it permission to notify you with updates, and before you know it, your phone's buzzing like a beehive with status updates, tagged photos, and friends checking in nearby….

There's no doubt that Glass apps will allow a fine degree of customization for how and when notifications arrive, but so do iPhone and Android apps. The trouble is, most of us choose to ignore these settings and face a steady barrage of notifications for emails, Twitter mentions, and a dozen other apps. Since Glass is on your face, these notifications will be even more disruptive.