Do you remember when you first learnt another European language at school? You had trouble with the pronunciation, you could not understand why they put the adjectives before or after the noun, why their irregular verbs were different from yours. These people sucked, their language was irrational; but at the same time it was fun.
What's happening here? Let us consider three languages. The first one is French. French is my mother tongue. French is usually considered as one of the most difficult languages in the world. Not everything is difficult in French though. For example, the sentence stress always occurs on the last syllable. The pronunciation is not very difficult either, once you have understood the rules. So it could be a nice and not-too-difficult language but, for some reason, French verbs are extremely difficult to use, the grammar is awfully complicated, and the orthography, well, we'd better not speak about it. In French schools, the pupils spend ten years of their life learning the rules, the variants of the rules, and the exceptions to the variants of the rules.
It would be nice to have a language where the verbs would be easier to use and where the adjectives would be always on the same side of the noun. I'm speaking about the English language. Alas, sometimes you need to speak English, not just read it, and the trouble begins. Each vowel may be pronounced in four or five different ways, and you never know which words should be stressed and which ones should be nearly mute. As a foreigner, you know that you may live in Oxford for twenty years, you may marry an English woman/man, you may even understand the rules of cricket, but you will never, never sound like an Englishman.
So what? Let's find a language in which pronunciation is easy. Yes, it does exist: Japanese. The Japanese language does not contain any weird sound, and the syllables are extremely simple. Of course you need to learn the grammar and the vocabulary again from the ground up, but it seems normal since that language has no common root with the languages you already know. So, is this the perfect language?
No, it is a new nightmare. You can speak the language, but you cannot write it, and you cannot read it, because the Japanese use the most incredible writing system in the world. They write their language with Chinese characters, but the Chinese characters were invented for a language which has no inflection, and which uses so many kinds of slightly different sounds (tones) that an alphabet would be either huge or inaccurate. Japanese is just the opposite: it cheerfully adds suffixes to the particles and particles to the suffixes, until the sentence is completely unreadable for a Western mind. And, as we have already seen, it uses very few sounds.
Anyway, they still decided to use the Chinese characters, and they called them kanji. Since the kanji were clearly not adapted to their language, they also invented a fifty-character syllabary (hiragana) for the inflections. Because it was not complicated enough, they created a second fifty-character syllabary (katakana) for various purposes, including writing foreign words. So you have it: the weirdest writing system in the world. And that language, which could be simple, nice, rational, is a complete mess. Just like English. Just like French. The Japanese children spend ten years of their life learning how to write their language, and after that more of them can read and write than in Western countries.
I can see only one explanation: we need complicated languages. It's something within us, we can do nothing about it: we love the subtle intricacies of each language. We don't think a language can be worth learning if it is simple. This is why Esperanto and Lisp will never win.