Twitter — The error message when tweeting is displayed underneath the tweet modal overlay, forcing the user to close the tweet modal to dismiss the error message.
Good examples of bad UI
Submit a Detail | For good UI have a look at Little Big Details
Twitter — The error message when tweeting is displayed underneath the tweet modal overlay, forcing the user to close the tweet modal to dismiss the error message.
Github — Github’s new colorful news feed icons fight with user avatars for attention.
Twitter — Twitter’s web client doesn’t display newlines while its iPhone client does.
Chrome Web Store — Google’s official YouTube Chrome app has inconsistent branding with YouTube itself.
Pandora — When hovering over the resize drag handle, the cursor changes to a hand instead of a standard resize cursor.
Gmail — When viewing an email, many of the icons’ actions are not obvious or intuitive, especially considering the similarity between the back icon and the reply icon.
Google+ — The main scrollbar is disassociated with the content it scrolls.