It’s nice to be important, but is it really more important to be nice?

The late British entertainer Bruce Forsyth had amongst his several catch phrases “it’s nice to be important but it is more important to be nice”.
Does this apply in our professional lives? After all, the workplace is a ruthless environment, where the tough survive, the Psychopath reaches the top, and those who are concerned with others tend to be cast aside. http://time.com/247/millennials-the-me-me-me-generation/ suggests that the millennial generation contains a higher proportion of narcissists than previous generations. So, is it ok to be harsh with others, who do not meet our expectations, in a professional context?
Most decent interview advice makes reference to the importance of being courteous with all of the people you meet on interview day. More than one or two job opportunities have been lost by a candidate being discourteous with the reception staff or car parking staff.
An article in Harvard Business Review suggests that optimal team performance occurs when there is a ratio of 5.6 positive comments to one negativehttps://hbr.org/2013/03/the-ideal-praise-to-criticism Whether you agree with this or not, we all tend to remember negative input longer and more clearly than positive.
When it comes to feedback in everyday interactions, most people have a negative mental filter. That is people screen out the positives and focus on the negatives. Interestingly, someone with narcissistic personality disorder may ostensibly have a positive mental filter, i.e. they remember the positives but forget the negatives because that enables them to maintain their grandiose sense of self.
However, for most people, negative feedback impacts them much more clearly than positive, and people remember the source of the negative feedback. The reputation of the feedback provider is built on how they are remembered. Just as the person on reception or the car park attendant may have the ear of the key decision maker in the interview you go for, so too people who deliver negative feedback build a reputation. Alternatively, providers of positive feedback and constructive criticism gain a commensurate reputation albeit harder to do so given the lesser impact of positive feedback. Which one do you want to be?