Tabindex-itis

Not every element should be keyboard focusable!

Do not apply the tabindex attribute to static text or graphical elements. Doing so will create an unnecessary tabstop for keyboard users.

A common mis-conception amongst developers is that screenreader users will not be able to access and read an element if it is not "tab-able". However, using their own special commands, screen readers can focus on all elements perfectly well, without the need for the TAB key or the tabindex attribute.

A tab stop on a static element will confuse users, because A) it will be interpreted by the screen reader as having a non-interactive role, and B) any attempt to interact with the element (e.g. using SPACE, ENTER or ARROW keys) will be a no-op.

Unnecessary tabstops increase physical discomfort for some users - for example if using a binary switch rather than a traditional keyboard.