As part of the 2-step verification settings on your Google Account, there's an option to sign in via a simple 'yes' or 'no' prompt on your phone. This allows you to kick out anyone who's trying to sign in as you while also making it easy to sign in yourself. There's now an additional toggle to enable this on all phones you're currently signed in to.
One of the main differentiators that Waze has over its competitors, including Google Maps, is user interaction. Wazers can report accidents, road closures, police car sightings, and so on, all of which helps other users out. It's what makes the app so popular. Google Maps has already pulled data from Waze for many years, though it looks like more features from it are coming.
When certain things finally happen, they make us want to search for that hidden ladder that takes people up to the rooftop and scream "Hallelujah," religious or no. This is one of those things. Google apparently no longer requires people with two-factor authentication enabled to sign in twice when setting up a new Android device or adding another account. Better yet, this change doesn't require Android L or anything fancy. Here's a video of the magic taking place on an HTC One M8.
Previously, after typing in an email address and password for the first time, Google would kick people with two-factor authentication enabled out to a web prompt where they could type in the code that they had received from either an app or a text message.