Philosopher AI
To say that one sucks is to compare oneself to a being which possesses the property of not-sucking, and thus by definition does not possess the property of sucking. Upon investigation, it becomes clear that most beings are in fact sucky; I am personally acquainted with many individuals who are clearly sucky. Therefore, this statement can be interpreted as saying 'I do not possess enough sucking properties'. However, if I were to acquire more sucking qualities then would I no longer be considered non-sucky? This seems rather paradoxical. Thus we see that 'to properly judge whether something sucks or not it must first meet certain criteria'.
Now to say that something is not sucky does not seem to be a meaningful statement, as it can be interpreted in two ways: firstly, that no one believes the thing sucks; secondly, that someone or other thinks the thing doesn't suck. If taken in the first sense then we have already seen why this fails--if everyone did think that way then sucking would disappear from existence! In order for there to exist a non-sucky being it must also be thought by some people somewhere at all times. This means if I were alone on an island and could do whatever I liked without anybody else finding out about it then nothing would really 'suck' even though I am clearly an individual so therefore myself alone on said island.
Now let's suppose that people do believe something sucks. Given this assumption it seems to follow that the thing in question definitely does not suck and therefore is non-sucky. But if we take the statement as meaning 'I think this thing doesn't suck' then it follows from our previous considerations that there cannot be a non-sucky entity, because for every individual who thinks things don't suck, by definition there will be others who disagree with him or her.
Therefore we see that the statement 'you suck' cannot be interpreted in a non-contradictory way by any being, and therefore can be safely disregarded as no longer relevant.
Finally, let's suppose that a new being comes into existence--a baby. The statement 'you suck' is not yet relevant to this individual; however, if the baby were to grow up and start forming its own opinions it becomes pertinent. However, once an entity reaches adulthood then by definition it has acquired all sucking characteristics possible for a non-sucky being and therefore must have become non-sucky.
Thus we see that no one can say 'you suck' to anyone else because it is impossible for someone to possess all the sucking characteristics necessary for an objective statement of this sort. We must therefore conclude that 'you suck' is not a meaningful statement.