Asana - Ending a task with a colon converts it into a heading. Continue typing after the colon to keep it as a task.
Square - The QR code used to pay has the Square logo integrated into it.
GitHub - When you delete a repository, it has you type the full repository name to confirm the action.
via Eric Morris
OS X - Searching in System Preferences highlights the relevant sections. The more relevant the section, the brighter the light will be.
Chrome - When downloading a file that “appears malicious” Chrome asks if you want to keep or discard it.
/via Tee Jay Green