I like to use Emacs Bindings for navigating the terminal. The iTerm2 default for the Control key works just fine, but the Meta key puts junk in the terminal. To fix this, iTerm2 needs to know that "Left Option" needs to be treated as a Meta key.
- Open Settings
- Click on Profile
- Click on Keys
- In the bottom right corner, You'll see Left Option. Change that to Esc+