These auxiliary verbs shall, will, may and can; also must, have to and should are the most difficult part of English grammar to me

From what I've seen of Dutch grammar, you've got some complicated verbal paradigms, too. For example, the modal particles dan, eens, even, maar, misschien, nou, ook, soms, and toch. Ga maar zitten is polite, but can you say ga zitten for a stronger, ruder sense?

Ceci n'est pas un seing.