A design is intuitive when people just know what to do and they don’t have to go through any training to get there When a design is not intuitive, our attention moves away from what we’re trying to accomplish to how we can get the interface to accomplish what we want.

Intuitive design happens when current knowledge is the same as the target knowledge.

The process of design starts with exploration, but ends with refinement. The best designers carefully move from one to the other, making sure they spend enough time exploring before locking themselves into a design approach.

Good design, when it’s done well, becomes invisible. It’s only when it’s done poorly that we notice it. Think of it like a room’s air conditioning. We only notice it when it’s too hot, too cold, making too much noise, or the unit is dripping on us. Yet, if the air conditioning is perfect, nobody say anything and we focus, instead, on the task at hand.

Good design, when done well, should be invisible.

Users scan a page looking for trigger words. If they find a trigger word, they click on it but if they don’t find it, they go to search. That’s the way it works on 99% of sites, although Amazon is an exception. That’s because Amazon has done a great job of training users to know that absolutely nothing on the home page is of any use.

In all situations where bad design decisions were made, people lacked some information that would have helped them make the right decision.