What are typical dutch expressions? Expressions originate from various cultural, historical, and linguistic sources within a particular language community. 

Expressions come from history, occupation and trades, literal meaning, folklore, other foreign languages, wordplay, insults and stereotyping. Interesting. Let me think, obvious is that when you memorize these phrases and use it correctly, people will be impressed by your knowlegde of dutch language. Lesson one.

De aap komt uit de mouw - The ape is coming from your sleeve - meaning the truth comes out.

De mazzel! De ballen! - Literally meaning "the measles" and "the balls" - expression to say goodbye (not in a formal environment).

Je gooit er met je pet naar - You are throwing your cap at something - meaning not putting enough effort to succeed.

Ik schrik me een hoedje - I was scared to death - meaning my scare makes my hat shake the meaning is a little less harsh then using the word death in your sentence.

De knoop doorhakken - To cut through the knot - refers to the legend of Alexander the Great cutting through the intricate Gordian knot - meaning to make a decision.

Maak je borst maar nat - Make your chest wet - Prepare for something hard or difficult, this strange phrase comes from the practice of splashing water on one's chest to prepare to  dive into cold water.

 Je ziet beren op de weg- Meaning "people who only see bears on the road" - this refers to pessimists.

De pijp uitgaan (je gaat de pijp uit voordat je het doorhebt) - To exit the pipe - meaning to pass away (slang).

Steek die veer maar in je reet  - You can put the feathers in your butt - meaning that you give someone a compliment.

Helaas pindakaas- Too bad, peanut butter - meaning to imply when something unfortunate happens.

I left the bad things out, any additions? Do what The Dutchies do...