Amsterdam is overdue one and security is relatively slack (that maybe why they have not done anything here yet, don't shit on your own doorstep etc).
The Dutch though, inspite of being a bunch of entitled, righteous, cheeseheads are not particularly hated by anyone and the tiny size of the country vs the huge organised crime outfits here would make it difficult to operate if your activities threatened the ongoing business operations of said crime organisations.
Holland is open for business, all business above all else.
Still though, it would not surprise me if an incident occurred and it would be easy to pull off.
Other low hanging fruit that would get my bet would be pretty much any of the spanish regional airports, Malaga for example, security there is a secondary priority to standing about chatting.