What do expats usually find confusing about taxes in the Netherlands?

I've noticed that Dutch taxation can be surprisingly difficult to understand for people who move to the Netherlands, especially when their financial situation involves more than one country.

For someone new to the Dutch system, the confusing part isn't necessarily the tax rate. It's figuring out which rules actually apply to them.

For example, an expat might have:

• Employment income from a Dutch employer
• Savings or investments outside the Netherlands
• Income from a business
• A previous tax residence in another country
• Cross-border financial obligations

That's why simply searching for an "expat tax advisor Netherlands" isn't enough. I'd personally look for someone who understands both Dutch taxation and international situations.

Another thing I've learned is that tax questions shouldn't always wait until filing season. If you're planning to start a business, change your employment situation, or move assets between countries, understanding the tax consequences beforehand can prevent problems later.

For anyone who has moved to the Netherlands: what tax-related issue surprised you the most after becoming a resident?