Tool-tip glasses

You maybe wondering.. "What's a tool tip?" If you hover the mouse pointer over a button for a few seconds then sometimes a little yellow hint appears explaining what the button does, this is known as a "tool tip". An example of a tool tip

Recently, at a friend's house, I was confronted with a unfamiliar TV remote control, I hovered my finger over one of the buttons, I genuinely expected a tool tip to magically appear. To my surprise nothing happened. I think I maybe loosing my mind...
Anyway, it gave me a brilliant idea... tool tip glasses, these would work by overlaying computer graphics onto the real world.
Such technology in the future could be built discretely into normal glasses.

Example applications

• 'Traditional' tool tips, (explaining unfamiliar technology, like remote controls)
• Warnings to say when objects are dangerously hot, this would be useful in the kitchen (a thermal imagining sensor would need to be included)
• Facial recognition to display a persons name when you see them, this would avoid those embarrassing moments when you meet a distant acquaintance and can't quite remember their name (this could be triggered by detecting uncertainly levels in your voice)
• Facial recognition to warn of dangerous criminals you may see but not recognise on the way to work. (this would need to have some wireless network link to a crime database)