Change Unity's default MonoBehaviour template
If you're like me and like your tab indents to use spaces rather than tabs, and you always remove the standard comments above Start and Update, then this little tips might be useful.
Go to /Applications/Unity and Show Package Contents on the Unity.app. Navigate to Contents/Resources/ScriptTemplates. Here, you'll find all the template Unity uses. Edit as you wish!
These files will be overwritten the next time you update Unity.