The trained observer can often spot difficulties and solutions that even the person experiencing them does not consciously recognize. It is because most people are unaware of their true needs, and discovering them requires careful observations in their natural environment.
The exposure effect has always been a primary tool of propagandists. Ubiquitous positive depictions, such as these of Vladimir Lenin, are commonly used to increase the likeability and support of political leaders. Similar techniques are used in marketing, advertising, and electoral campaigns.
Use constraints to improve the clarity, usability and intuitiveness of your design
Constrains, as methods of limiting the actions that can be performed on a system, simplify usability and minimize errors. For example, dimming or hiding options that are not available at a particular time effectively constrains the options that can be selected.
Proper application of constraints in this fashion makes designs easier to use and dramatically reduces the probability of error during interaction. Simply put; constrains simplify usability and minimize errors!