Efficient & Useless

One definition of Interaction Design is:

“designing interactive products to support people in their everyday and working lives.”

Yesterday, at San Diego airport I saw this great example for an efficient system that is useless to most of its users.

Persona:

• User A: a person visiting the bathroom
  
• User B: a cleaning crew personal

Task:

• User A: wash and dry hands
• User B: keep the bathroom clean
  

Design:
Position the automatic paper disposer/machine right above the garbage hole. Minor side-effects may include: providing the user A with a wet paper to dry his hands and direct disposal of paper without the 'need' for user A to use it...

User B is very happy with the design. I've actually met him.

E.T.