Which country is better to live and work in? Belgium, The Netherlands or Germany?

I’m Belgian myself, but have good friends in all three. I live in Slovakia, but, if my circumstances would be different, I would

Definitely

For

The Netherlands.

excellent salaries
extremely well organised country in every way
friendliest population of all three, by far
huge chance that you get to go to work by bike, see what Peter Sagan says:
open-minded people
beautiful cities
you can go to the Belgian coast, as many Dutch people do
if you don’t speak Dutch: everybody speaks English
in Belgium you would probably need to learn French (my Slovak wife speaks 5 languages but couldn’t find a decent job in Belgium, because she doesn’t speak French)
Better press, better media and better literature than Belgium (ok, not better than Germany in this case)
great policies on many ‘controversial’ issues such as cannabis, euthanasia, etc
people are easiest to talk to, far easier than Belgians and a bit easier than Germans