Many people believe that language is just a way to communicate and share ideas. However, a language is always more than that. It often also seems to serve as a social filtering tool. The idea is that your language reflects how smart you are. If you say certain 'sophisticated' things, then you could come across as well educated and highly intelligent. With certain 'errors' you could immediately lose a lot of prestige. Often it could imply that you lose certain discussions...
Dutch is no exception, although I personally believe that in other languages like French this social filtering system is much more active. At the same time, also Dutch people love to be pedantic and sometimes they like to point out grammatical errors, certainly if they disagree with you. The idea is that if what you say or write is not entirely grammatically correct, then somehow you lose credibility. Why should someone listen to you if you do not even master your own language?
I must say that being pedantic is one of my guilty pleasures. At the same time, I mainly see it as entertainment, because real life is always different from theory. Some people that have a so called 'wrong' usage of language can still be millionaires and have a great sex life, while others that spell and speak impeccably can still lead miserable lives.
My piece of advice would be to take all this very lightly and at the same time.... it can be fun sometimes to tease other people and correct them :) Dutch people do it all the time and let's be honest... the idea that you could outsmart Dutch people now and then, could be an entertaining thought, right? So let's go with 4 great examples....
1 You either have it or you don't
Hij heeft means he has. This would not be rocket science, right? The truth is that many Dutch people say it 'wrong': hij heb or hij hebt. The 'only right and presigious form - that I always teach - should be hij heeft
Here is the strange thing... hij hebt is not that strange at all. In fact it would be more logical than hij heeft. The only thing is that just like in English hebben (to have) is irregular. Also in English it would be more logical to say: he haves, but everyone says he has. Probably has is easier to pronounce than haves, so this might explain why have in English is also irregular!
In spoken Dutch you may quite often hear: hij heb or hij hebt, certainly when people talk with certain regional accents. If you like to come across as well cultured, then make sure that you always say: hij heeft.
2 Do you really own it?
Another thing that many Dutch people confuse is jouw and jou. If you write jouw then it means your and it means that you own it. Here are some examples: jouw hond (your dog) & jouw paspoort.
Do you already know how to say I love you in Dutch? Then would be: ik hou van jou (not: ik hou van jouw). Another example would be: ik zie jou (I see you) and not: ik zie jouw.... You could say: ik zie jouw hond, and then it means: I see your dog.... If you just understand that jouw means possession, your, then you could already outsmart many Dutch people. The weird thing is that a huge part of the Dutch population is still struggling with this ;)
3 Something beyond comparison
In English you could say: Italy is warmer than Holland, and in Dutch you would say: Italië is warmer dan Nederland. This is quite easy right? Not for many Dutch people however: instead of dan, many people use als. They will say: Nederland is warmer als Italië....
The rule is just like in English. If there is a difference, you use dan (than): de Noordpool is kouder dan Nederland. You use als when it is the same: zo koud als ijs (as cold as ice) or even koud als de Noorpool (just as cold)
Sure.... it might look like a small thing and yet.... quite often Dutch people love to correct eachother and laugh loudly when instead of dan you use als. The reaction of the person that gets corrected is often quite annoyed... So many people say this 'wrong' all the time and that is why some Dutch linguists suggest that it should not be seen as a mistake anymore....
4 It is always I....
Would you know how to say in Dutch: you are not better than me? Probably you would say: jij bent niet beter dan mij or: je bent niet beter dan me.... The sophisticated form in Dutch would be: jij bent niet beter dan ik. The idea is that it is a shorter version of: jij bent niet beter dan ik ben......
So here are more correct versions: jij bent niet beter dan hij (not hem) & jij bent niet beter dan zij (not haar) and jij bent niet beter dan wij (not ons).
Once again, in English you would often say: you are not better than me / him / her/ us. I have to admit that jij bent niet beter dan mij would be quite a reasonable construction, but many pedantic Dutch people keep insisting that this is so wrong on so many different levels....
By the way, if you like to put the focus on yourself then instead of I you can say me! In Dutch you would not say me / mij but ik, ik ik! Another informal version could be ikke! So... if you want to answer the question; wie is altijd charmant en intelligent? (who is always charming and intelligent?) then if you think it should be you, then start shouting: ik! Not me or mij, because then you sound like a tourist ;)
So now you have 4 ways to outsmart Dutch people. I would recommend however, to be quite discrete about it. If you point these 'classical errors' out to Dutch people, chances are high that all of a sudden they will start to focus on your mistakes and if Dutch is not your native language, it would be an unfair competition....
At the same time, social prestige always plays a certain role in language and although in Dutch it is still relatively subtle in compartison to other languages, it is always there! It could be useful for you that you realise that it simply exists... I guess that also in your language people like to debate about 'right' and 'wrong' things that you can say.... If you have some good examples, then please share them here!