Everyone has a favourite mug, but it's not always a conscious decision.
As humans we possess an inherent desire for habit and comfort. Think of your favourite mug at home, now think of your favourite mug at the office. I’m not trying to prove which type of mug is the most popular, this use of everyday habit memory was to prove that you have a favourite mug even though you may not have realised it.
The satisfaction of drinking from your favourite mug is not one you really notice, but it becomes noticeable when you’re given a drink in the wrong mug, i.e. when the habit is changed and the comfort is taken away.
This is the same in design. If you enjoy an experience you will return again. If there is something missing or "incorrect" about an experience it will dissatisfy or jar, just like when somebody makes your tea or coffee in a different mug.
The beauty of human nature is in diversity, stack everybody's favourite mugs in a cupboard and inevitably there will be a combination of sizes, thicknesses, colours and shapes.
When you're designing a product or an experience you need to take into account this diversity within the opinion of "perfect". Start with the widest range of possible audience then simplify back, eliminating the least important one at a time until you reach your core group. This will ensure you're pleasing the most important people and not becoming too generic, this is important because a generic experience will target nobody and isolate each individual, leaving them feeling “this is not designed for me”.
Knowing your audience is the key to finding this delicate balance. Get out your comfort zone, meet your potential users, think of experiences from their perspective. This will help you write user stories and map out what your audience really want to do with your product, not what you want them to do.
I recently heard a great example of the difference a simple change can make. A web form was being designed on a banking website for young adults signing up for their first bank account. The designer met the target audience and took into account their feelings at this new experience. They feel like they’re entering the adult world and are often a little out of their depth. With this in mind the designer tailored the site wide list of options under “title” to disclude names such as “professor”. The audience would never notice what is missing, but they would feel uncomfortable if it were included, as it would make them question whether they were in the right place, or isolate them. Using perspective gained from meeting the target audience the designer was able to pay more attention to detail within the user experience.
Google’s search engine is the definition of simplicity, allowing users to find what they're looking for again and again and take it for granted. Yet the engine hidden behind that simple search bar is so complex and sophisticated. Simple design is not simple through and through, to achieve simplicity you need much more than simple thoughts. You can start by boiling the problem down to it's essential requirement, but the solution requires complex thought, ample time, plenty of research and on going performance monitoring.
So to conclude, simplicity is deceptive. It is not easy to achieve and it's greatest success is ultimately to be ignored and enjoyed on a subconscious level, like your favourite mug.
Although I hope that tomorrow morning you will sip your tea with a small smile on your face.