A 'smart aleck' might not be aware of the repulsiveness of his knowingness.. One should avoid behaving the way he doesn't want the others behave towards him.

In society people who throw themselves forward in almost every subject and be a smart aleck thinking that they know everything the best, are named as "wiseacres". Such people are generally known by their putting forward an idea without fail in almost every subject –regardless of their knowing something about it or not- and by their having something to say in every conversation.  

Wiseacres regard themselves so important that they believe the world rotates around them.  They think that they are in the center of every incident. They believe that if they are not there, if they do not talk, if they do not give an opinion about a point; people will miss out very important information.  For that reason, they can't stand still without interfering in every subject discussed before them. Such way of behavior turns into a kind of disease for such people.  They believe that they say the most important things even in subjects that are not their concern and that they know nothing about.  Even about situations that their help is not requested, their opinions are not asked or even in situations they are asked not to interfere at all, they can't control themselves and want to interfere somehow.  

One of the most important indications of this behavioral disorder is that they keep reminding people things that everyone can easily think of and say things as if they have invented them and as if no one else knows about those, before anyone can say anything. For instance if there are two alternative routes to follow to a destination, it is apparent that the related person will prefer one of those two routes.  This is a known fact.  However a wiseacre can't resist stating his opinion even about this. He would say, as if he were the first one to discover these two alternatives, "go from here, if that does not work, you can go from this way as well".  

One of the most important points that such people are mistaken is that, despite their such behavior, they believe that people around them find them very sympathetic.  They think that everything they say are very much liked by others, that their opinions are considered to be very important and that people need their such informative meddling. They believe that if they did not participate in the discussions, if they do not give their opinions and state their ideas, things will go wrong, things will not be solved and that people will not be able to find out what to do.  

However, things are never as they assume. Moreover, leaving aside being sympathetic, such wiseacre state of mind would be highly repulsive on such people. Even if the things they say are really correct, even if they bring up a matter or a detail that is really needed, people would feel uncomfortable with their such participation. That is because what is important in an incident is not settling the matter and solving it; it is the morality that people live by during this process; ensuring a peaceful, serene, comfortable environment that people can live altogether is at least as important as the targeted result. Knowingness may bring tension, discomfort and unrest along with it. Instead of being subjected to such behavior; instead of getting benefit from that person's ideas; people would prefer to handle that subject from a more complex route in peace.  

However what is important here is that even though everyone is explicitly aware of this situation and is feeling the discomfort of it, the smart aleck almost never realizes it.  That person might think that the normal course of life is going on and that he is helping the people around him. However he is unaware of the fact that the discomfort he causes for people around him is far more important than the benefit his opinions will provide.  

What this person should do in such a situation is to never forget that the course of events goes on and the world rotates even if he is not there. The problems will be solved and people will come up with good ideas even if he is not there. Everything is not working out perfectly "only because he is there".  

One of the ways to explain this to that person is to ask him to analyze another smart aleck he sees around him. He would too mention that he is very much disturbed from a person behaving with "I know everything the best" attitude, who behaves as if he knows all the answers, who unnecessarily meddles with everything even though his help is not asked for, who expresses his opinions about every subject, who gives advice to everyone, who criticizes, who says that he doesn't like the methods and attitudes of the others.  

However he is still unaware of the fact that he keeps behaving in the very same manner that he doesn't like the others to behave towards himself. Since he doesn't think on his lower self profoundly and in detail on this respect, he is not aware of the repulsiveness of knowingness and the dimensions of the discomfort he causes for the people around him.  

To show this truth to him might cause him –by the leave of Allah- to think more sincerely and to attempt to change his morality. If such a person becomes a little aware of this fact, insha'Allah, he would change all his character and attain a more sincere, much better morality.