Gmail - The “Attach files” icon changes after the first attachment was uploaded.
Facebook - The notifications icon shows a different side of the globe depending on your location.
/via Thomas Park
Mixpanel - When changing your password, the field for the current password has an old style key, and the new password has a modern key.
/via Timothée Boucher
Google Maps - The street view icon on Google Maps has a surfboard and tropical shirt when in Hawaii.
iOS - If you tap the camera icon in the lock screen of iOS 5.1, it bounces up to encourage you to slide.
Safari - When pinning a topsite, the icon of the needle looks like it’s really going in.
Chrome - When uploading files, the usual blue rotating circle in the tab bar becomes gray and spins counterclock-wise.
/via Julian Peters
YouTube - The play icon changes to a replay icon at the end of the video.