Etiquettes can be defined as 'unwritten norms of behavior that make interaction pleasant'. A little bit of care exercised in displaying etiquettes can open up channels for communication and help in creating a better image of the self/the organisation.
Though fairly simple to follow, they are often either ignored or not displayed.
Isn't it often that we approach a 'pleasant' person, rather than a 'grumpy' person, when we desire to get our issues resolved?
Isn't it also that a 'pleasant' interaction adds a smile to our day and influences our behavior in turn; while an 'unpleasant' interaction can spoil even the best of days/moods.
Since we all face this challenge at some point, with some person and in some situation or another, it is important to be aware of and adopt a few etiquettes in our interactions with others, whether in a formal or in an informal situation.