Your question is unclear. I would reword it.

The same reason why people ask and answer questions for no "apparent" reason. It's provides a non stressful way to pass time online.

So is the case with first impression. In as little as 8 to 30 seconds, people form fairly lasting impressions about you - impressions about your intelligence, success, confidence, competence, physical fitness, professionalism, etc. The axiom "you never get a second chance to make a first impression" is so true. And it's compounded by the fact that people generally do not change their minds about someone once they've formed that impression. http://www.bizjournals.com/charlotte/stories/1998/03/09/smallb3.html Within the first three seconds of a new encounter, you are evaluated even if it is just a glance. People appraise your visual and behavioral appearance from head to toe. They observe your demeanor, mannerisms, and body language and even assess your grooming and accessories watch, handbag, briefcase. Within only three seconds, you make an indelible impression. You may intrigue some and disenchant others. This first impression process occurs in every new situation. Within the first few seconds, people pass judgment on you looking for common surface clues. Once the first impression is made, it is virtually irreversible. The process works like this: * If you appear to be of comparable business or social level, you are considered suitable for further interaction. * If you appear to be of higher business or social status, you are admired and cultivated as a valuable contact. * If you appear to be of lower business or social standing, you are tolerated but kept at arm's length. * If you are in an interview situation, you can either appear to match the corporate culture or not, ultimately affecting the outcome. http://entrepreneurs.about.com/cs/marketing/a/uc051603a.htm http://psych.utoronto.ca/~joordens/courses/PsyA01/Chapter15/sld005.htm It takes just a quick glance, maybe three seconds, for someone to evaluate you when you meet for the first time. In this short time, the other person forms an opinion about you based on your appearance, your body language, your demeanor, your mannerisms, and how you are dressed. With every new encounter, you are evaluated and yet another person’s impression of you is formed. These first impressions can be nearly impossible to reverse or undo, making those first encounters extremely important, for they set the tone for the all the relationships that follows. http://www.mindtools.com/CommSkll/FirstImpressions.htm Researchers led by Dr. Gitte Lindgaard at Carleton University in Ontario wanted to find out how fast people formed first impressions. They tested users by flashing web pages for 500 msec and 50 msec onto the screen, and had participants rate the pages on various scales. The results at both time intervals were consistent between participants, although the longer display produced more consistent results. Yet, in as little as 50 ms, participants formed judgments about images they glimpsed. The "halo effect" of that emotional first impression carries over to cognitive judgments of a web site's other characteristics including usability and credibility. http://www.websiteoptimization.com/speed/tweak/blink/ According to folklore and conventional wisdom, the first impression you make upon meeting a person sets the tone for the subsequent development of the relationship. A bad impression, therefore, constitutes an irrecoverable error. That being the case, you should always make it the highest priority to look your best in any situation in which you might meet people, and women in particular. Irrational!! Shallow, superficial people judge others by "first impressions". It is an indication of intellectual laziness of an unwillingness and possible inability to reason deeply, analyze, and make informed decisions. A woman who makes a snap judgment of you based on a "first impression" is hardly worth bothering with. http://personal.riverusers.com/~thegrendel/hmw2b.html "Our two minds .... One is an act of the emotional mind, the other of the rational mind. In a very real sense we have two minds, one that thinks and one that feels" (Daniel Goleman, Emotional Intelligence, Bloomsbury Publishing, London, 1996, page 8). This rational mind is also called the faculty of logic and reason. The Upanishads say that these two are opposite in nature. Modern psychologist also have observed it, but they are not very sure about it: "At the same time, reason sometimes clearly seems to come into conflict with some desires (even while not being in conflict with others) giving us the impression that reason is separate from emotion". http://en.wikipedia.org/wiki/Reason The emotional mind is subconscious mind and the rational mind is the conscious mind. The Upanishads call the emotional component of mind as Chitta and the rational component of mind as Manas. The nature of Manas changes gradually and minutely with every perception and learning. Intuition is perception which is received without apparent effort, quick and ready insight seemingly independent of previous experiences or empirical knowledge. First impression is formed by emotional mind and last impression is finalised by rational mind. It has been estimated that about 70% of men and 90% of women use emotional mind most of the time. Using observations through millenia, wise men of the yore generalized that first impression is hard to change for most of the people. This wisdom was passed on to folklore and esoteric texts.