wat is echt nederlands tradition?

Hii, welcome @Woo-Jin. One of our traditions is our holiday Sinterklaas. It's like an old white bearded guy giving presents to children. Kinda looks like Santa claus but then without the elves and the reindeer. 

People call windmiles, clogs and tulips also typically Dutch, but to be honest I don't know. No one ever walks around in clogs and tulips are Turkish i believe from originee. 

I do love the stroopwafel. That's really Dutch it you ask me.

What's also typical Dutch is cycling, cheese and eating dinner at 6 P.M. and like @Starberry said, "de stroopwafel" or syrup waffle is a typical Dutch cookie; a waffle with apple or cinnamon syrup inbetween it. If you happen to go to a Dutch market and they sell them there, they're usually warm, freshly baked and huge (bigger than stroopwafels from like a supermarket called "Lidl" for example where I often get my stroopwafels from because those are pretty great).

You're supposed to put a stroopwafel over the top of a cup of hot coffee or tea for a small while and let the warmth/steam from that drink soften the stroopwafel a bit and then eat it. I personally never did this, nor knew this and I am Dutch but it sounds like fun!