Why is the German language so complex?
Some people don't like the German language, but I believe it is one of the most beautiful languages out there; because, behind all that nonsense (for non-German speakers) and strong words, there is a rich structure that reflects one of the most organized and correct societies of our planet.
If you wish to learn German you should start with their personal pronouns, which are: ich, du, er/sie/es, wir, ihr, sie and Sie (I, you, he/she/it, we, you (plural), they and you (formal)), with a simple Hallo! to greet someone, and Danke to say thanks.
What really makes the German language a complex one, it's its use of "declension", which include the nomivativ, akkusativ, dativ and genitiv. Each one of them changes articles, adjectives, and much more depending on the location of a word in a sentence.
For example, if a word is the direct object of the sentence (the one that receives the action of the verb), that would be the akkusativ case. If we're talking about with whom that particular action is made, that would be the dativ case (also, it is used after prepositions). And finally, the genitiv case—which is not that easy to spot sometimes—, is generally used to indicate possession.
One of the best ways to start learning the German language is through www.duolingo.com, which is a free website where one can learn almost any popular language in the world. Another good resource, but for the intermediate audience, is Easy German, a YouTube channel where Cari and Janusz go and interview random people in different parts of Germany. I think that Easy German is one of the best ways to get familiarized not only with the German words and sentences but also with the way a German speaker talks to people.
Some people may find the German language too restrictive and with a strange order in their words to form sentences. But this is just a reflection of how serious the German people take things in life. The Germans are well known for their punctuality, respect, and order in their everyday life, and once you start learning the German language, this aspect becomes crystal clear to any new learner.