What mistakes made me get a 50 on the written exam?

[opaque onyx]

Two weeks ago, I took my second German exam at the Goethe B1 level, and unfortunately, I scored 50 in the written section. I want to know why my score is so low. My answers were as follows
Teil 1 :
Liebe Sare,
Ich hoffe, dass bei dir alles in Ordnung ist. Endlich habe ich ein bisschen Zeit gefunden, um dir zu schreiben. Am letzten Wochenende waren wir im Norden. Zwar war das Wetter warm, aber es hat mir Spaß gemacht. Wir haben sowohl im See geschwommen als auch geangelt. Zum Mittag hat Ali Fisch gegrillt, und das war lecker. Auch meine Freundin aus Berlin war dabei, und wir haben den ganzen Tag nur Deutsch gesprochen. Ich möchte dir die Fotos zeigen. Wie wäre es, wenn wir uns am Freitagabend bei mir zu Hause treffen ?

Teil 2 :
Ich bin dafür, dass die Arbeit am Wochenende verboten sein muss, weil jeder Mensch Erholung braucht. Es ist sinnvoll, wenn man die ganze Woche arbeitet, dann hat man natürlich mit der Zeit keine Energie mehr. Ich habe eine Freundin, die sieben Tage in der Woche voll arbeitet. Zwar kann sie viel Geld verdienen, aber leider hat sie später starke Rückenschmerzen. Man sollte nicht nur sich entspannen, sondern auch Zeit mit seiner Familie verbringen. Meiner Meinung nach sollte man am Wochenende nicht arbeiten, und in diesen Tagen kann man verschiedene Freizeitaktivitäten machen.

[sour kestrel]

Zwar war das Wetter warm, aber es hat mir Spaß gemacht. -> Grammar is fine, but content doesn't make sense
comma before "und" is almost always wrong
Es ist sinnvoll, wenn man die ganze Woche arbeitet, dann hat man natürlich mit der Zeit keine Energie mehr. -> Grammar is fine, but content doesn't make sense
(and some smaller stuff)

[fleet garnet]

The marks for the writing section are more than just the correct grammar and spelling. You have to accurately address the question, and write in a way that shows clear thought. In the case of the letter to a friend, you have to also display correct use of tone along with proper formatting. For example, the sentence "Ich hoffe, dass bei dir alles in Ordnung ist." doesn't sound right for a email to a friend. It would be better to say something more friendly, casual, and warm like, "ich hoffe, es geht dir gut" or even just "wie geht's dir?". And after an opening greeting, the next word starts with a lower-case letter, because it's technically considered the same sentence. (Written without line breaks, it would be , "Liebe Sare, ich hoffe...." Additionally, you didn't even sign off the email. Something like, Liebe Grüße, Moumel would properly close the email while continuing to express the warmth of a friendship. For the second part, showing coherent thought and structure to an argument is important, along with appropriate language. I do think that some of your arguments don't seem quite connected logically, so it maybe have limited your ability to use connecting language. You could have also used some more common phrases that are used to show opinion and argument, like Ich finde, dass.... or zum Beispiel... Sorry you didn't do as well as you would have liked. It can be hard to adapt to the specific style of an exam. I'm sure if you just looked up some examples of appropriate writing styles, you would learn and adapt quickly, though.

[short bluff]

@opaque onyx How do you feel about other modules?

[plain ice]

I want to point out that, as I know, you should but a farewell part in the email like:

Mit freundlichen Grüßen,
…

And there should be something like a conclusion in the second teil, at least say something like:
Abschließend glaube ich, dass jede Person eine verschiedene Meinung halten kann. (I think that this is a good phrase for a B1 exam)

And don’t forget that the topic is the most important thing, maybe you write a text like a native speaker but in the end you get 0 because it doesn’t cover any of the mentioned points. You didn’t provide us with the given in the exam so be aware from that.

Best of luck my friend

[surreal trout]

You have mentioned here that:

You have to accurately address the question, and write in a way that shows clear thought

Now, it seems like you are talking about the CEFR levels.

I have tried looking up and down the internet, and I haven't found the answer to my questions.

1. Do you think that the descriptions of each of the CEFR are somewhat descriptive but arbitary?

2. (do you know) What EXACT criteria is used to grade somebody inter- and intra- the CEFR levels?
   Meaning: do the teachers have a more structured examination guide, or do they hand out marks based on strong hunches

also,
since you're a native German speaker and if you haven't tried to take a standardized test in a foreign language (not English), it could be that you might have never thought of the queries above and that is okay.