Anyone who operates a computer, and uses software for power point presentation, knows how many times it is necessary to consult others to get going on certain counts. The simplest of office equipment such as printers and scanners cannot be operated without instructions and some outside assistance. Many products ranging from the faucets in the toilets to the glass doors in the office require multiple attempts — we twist, or press or turn before getting water to flow or push, pull or slide for doors to open up

Donald A. Norman a cognitive psychologist has written a book. The Design of Everyday Things in which he discusses why user-friendly design is not easy. It begins with our interactions with everyday things. The three critical elements to using things successfully are:

 

• visibility : the buttons to operate a faucet or turn signals in the car must be visible.
• appropriate clues : there should be visible clues or affordances e.g. lift, press, turn
•  feedback : feedback must be provided e.g.flowing water from the faucet or blinking direction indicator on being operated.

These three elements contribute to the makings of a usable design.

It may be necessary for a product to be subjected to five or six attempts to get the design right. Many products never do. It is necessary to understand the psychology of everyday things. It makes our life less stressful and more productive.